Introducing Aftermath: Hunt for The Anthrax Killer

Summary

Casefile True Crime - Summary of "Introducing Aftermath: Hunt for The Anthrax Killer"

Introduction

In the gripping episode titled "Introducing Aftermath: Hunt for The Anthrax Killer," Casefile True Crime delves into the harrowing events that unfolded in the wake of the September 11 attacks. Released on April 17, 2025, this episode sets the stage for an eight-part series that explores one of the largest and most perplexing FBI investigations in American history—the hunt for the anthrax killer. Hosted by Casefile Presents, the podcast leverages exclusive access to declassified materials and firsthand accounts to unravel the intricate web of scientific clues, human errors, and personal costs associated with the investigation.

Background: Anthrax Attacks Post 9/11

Weeks after the devastating 9/11 terrorist attacks, the United States was thrust into a second wave of terror—not from planes, but from invisible spores of anthrax. These bioterrorism acts involved letters laced with anthrax spores sent through the U.S. mail, causing widespread panic, shutting down government buildings, and overwhelming law enforcement agencies.

Narrator [00:01]: “Weeks after 9/11, a second wave of terror struck the U.S. but this time the weapon was invisible. Anthrax-laced letters sent the nation into panic, shutting down government buildings and overwhelming law enforcement.”

The FBI launched an extensive investigation to identify the perpetrator, grappling with a complex maze of scientific evidence, potential human error, and significant personal sacrifices by those involved.

Robert Stevens: The First Case

The series kicks off with the story of Robert Stevens, a 63-year-old newspaper photo editor from Lantana, Florida, who becomes the first known fatality of inhalation anthrax in the United States in decades.

Jeremiah Kroll [10:17]: “He walked into JFK emergency room at around 2 in the morning. And after they put him on a ventilator and got a chest radiograph, they sent him for a spinal fluid examination, looking for bacteria.”

Stevens exhibited severe symptoms, including chills, fever, disorientation, and vomiting, leading his wife, Maureen, to rush him to the hospital. Dr. Larry Bush, the chairman of infectious diseases at JFK Medical Center, initially struggled to identify the bacteria causing Stevens' meningitis.

News Anchor [11:05]: “You're lucky if you can see one or two bacteria that help you determine what type of bacterial process this may be. His was overwhelming. I saw an overwhelming amount of pus cells. That's a bad sign. That means there's havoc going on in your nervous system.”

Dr. Bush's diagnosis of anthrax was both shocking and alarming, as anthrax was rarely encountered in suburban environments and not commonly considered outside of rural, livestock-associated contexts.

Narrator [13:02]: “This is the moment that it all began right here. For the first time in 25 years, it seems that someone in America has anthrax in their lungs.”

FBI's Investigation Begins

Special Agent Scott Decker, an FBI agent with a Ph.D. in genetics from Harvard, was part of the FBI's newly formed hazardous response team deployed to Ground Zero after the 9/11 attacks. Decker's expertise positioned him uniquely to tackle the emerging anthrax crisis.

Scott Decker [02:40]: “Now it's obvious, I think, I think.”

The FBI’s concerns were twofold: investigating the anthrax attacks and preventing a potential secondary biological attack, likely orchestrated by Al Qaeda. The timing and nature of the anthrax letters suggested a methodical and premeditated bioterrorism effort.

Scott Decker [04:06]: “The second attack was going to become at any moment.”

Connections to 9/11 Hijackers

As the investigation unfolded, unsettling connections emerged between the anthrax attacks and the 9/11 hijackers. FBI agents discovered that some of the men who had visited crop dusting schools across the country, including Mohammed Atta—the ringleader of the 9/11 attacks—had shown suspicious behavior and interest in piloting crop dusters, which could potentially be used to disperse anthrax spores.

Jeremiah Kroll [20:27]: “They ground all crop dusters across the country. That solves the immediate problem, but they still have a larger issue. Are there other extremist pilots out there waiting to launch an attack?”

This revelation intensified the FBI’s urgency to link the anthrax attacks directly to the al Qaeda network responsible for the 9/11 attacks. The proximity of the anthrax patient's residence to a flight school frequented by hijackers added another layer of complexity to the investigation.

Challenges and Complexity of the Investigation

The investigation faced numerous hurdles, including misleading information, lack of immediate evidence, and internal challenges within agencies. The Centers for Disease Control and Prevention (CDC) initially downplayed the anthrax case as an isolated incident, causing friction with local health officials who suspected a broader bioterrorism threat.

Dr. Jean Malecki [15:00]: “I have a potential anthrax event occurring in my backyard here. I am the chief health officer here, and you're telling me not to act on this.”

Moreover, the Anthrax strain identified in Stevens' case was traced back to a laboratory source, suggesting the possibility of deliberate dissemination rather than a natural occurrence. Dr. Paul Keim, a renowned expert in anthrax DNA fingerprinting, played a pivotal role in analyzing the spores and confirming their origin.

Dr. Paul Keim [25:53]: “For the last 30 years, I've been involved in trying to develop DNA methods for precisely identifying strains of dangerous pathogens so that we can identify where they came from, link them together with outbreaks, and in particular, how they're related to biological weapons.”

Despite these scientific breakthroughs, the investigation stymied progress due to false leads, lack of concrete evidence, and internal disagreements within the FBI. Agent Decker expressed doubts about the case being conclusively solved, highlighting the lingering uncertainties surrounding the perpetrator's identity.

Dr. Paul Keim [08:21]: “I would not consider the case to be closed. In my mind, it certainly is not solved.”

Ongoing Uncertainty and Conclusion

As the narrative progresses, the podcast underscores the enduring mystery and unresolved questions surrounding the anthrax attacks. Nearly 25 years later, the true identity of the anthrax killer remains elusive, with many aspects of the investigation still shrouded in secrecy.

Kroll [06:08]: “What's weird is that almost 25 years later, most Americans still have no idea who is behind these attacks.”

The episode concludes by emphasizing the profound impact these attacks had on American society, shaping biosecurity policies and leaving lasting aftershocks that continue to influence how the nation responds to bioterrorism threats.

Scott Decker [35:05]: “The FBI just needs a little hard evidence, a link that proves who did this so they can stop more deaths.”

Notable Quotes

• Scott Decker [02:40]: “Now it's obvious, I think, I think.”
• Jeremiah Kroll [10:17]: “He walked into JFK emergency room at around 2 in the morning... looking for bacteria.”
• Dr. Paul Keim [25:53]: “I've been involved in trying to develop DNA methods for precisely identifying strains of dangerous pathogens...”
• Dr. Jean Malecki [15:00]: “I have a potential anthrax event occurring in my backyard here...”
• Scott Decker [35:05]: “The FBI just needs a little hard evidence, a link that proves who did this so they can stop more deaths.”

Conclusion

"Introducing Aftermath: Hunt for The Anthrax Killer" sets a compelling foundation for the series, weaving together personal stories, scientific investigation, and the relentless pursuit of justice. It highlights the intricate challenges faced by investigators and the profound uncertainties that still cloud one of the most enigmatic cases in American history. For listeners seeking an in-depth, engaging exploration of a true crime saga, this episode serves as a powerful introduction to the complexities and enduring mysteries of the anthrax attacks.

Transcript

[Narrator]

Weeks after 9 11, a second wave of terror struck the U.S. but this time the weapon was invisible. Anthrax laced letters sent the nation into panic, shutting down government buildings and overwhelming law enforcement. The FBI launched one of the largest investigations in its history, unraveling a complex web of scientific clues, human error and and personal cost. The gripping new podcast series, Hunt for the Anthrax Killer takes you deep inside the case, from the science that cracked it to the mistakes that nearly derailed it. With exclusive access to declassified materials and first hand accounts, this eight part series from WOOF Entertainment, CBC podcasts and USG Audio reveals how the attacks reshaped America and the hidden consequences that still linger today. Now stay tuned for a sneak peek of episode one.

[Scott Decker]

I mean, this was a huge crime scene. Most people don't think about it as a crime scene, but it was a crime scene of seven blocks.

[News Anchor]

The unthinkable happened today.

[Jeremiah Kroll]

The World Trade center, both towers gone.

[News Anchor]

There are survivors trapped in that rubble. Mayor Giuliani confirmed.

[Scott Decker]

Now it's obvious, I think, I think.

[Dr. Paul Keim]

We have a terrorist act of proportions.

[Jeremiah Kroll]

That we cannot begin to imagine at this juncture. It was the evening of September 11, about 12 hours after the terrorist attacks. And Scott Decker, a special agent with the FBI, was already on the move. He'd packed his bags and said goodbye to his family in Virginia.

[Scott Decker]

I was told to grab four of the guys, load up our Suburbans with evidence collection equipment, Hazmat gear, Tyvek suits, masks, gloves. We loaded up the trucks that evening. Oh, dark 30, September 12th. We started heading up to New York, I think five black suburbans in a row.

[Jeremiah Kroll]

While everyone else was trying like hell to get out of New York City, Decker drove all night to get in.

[Scott Decker]

As we went through Maryland, we went through Delaware on Route 95, the main corridor. We got to the Delaware Memorial Bridge and the big alert sign above the traffic. And usually the letters are in yellow, but in my memory it was orange. I don't know why, but I remember orange. And it just said in bold letters, New York City closed.

[Jeremiah Kroll]

They arrived outside Manhattan near dawn. But those orange letters were right. New York City was closed even to the FBI. Bridges were shut down, landlines were out and cell phones weren't working well. So Decker went to an FBI office in New Jersey just across the river.

[Scott Decker]

I saw a Blackhawk helicopter sitting on the grass between the office and the Passaic River. And I said, yeah, I need a lift over to New York. So he said, jump in. And we flew over Manhattan and we flew over ground Zero doors opened on the Black Hawk. And as we flew over through the smoke, we just looked down and it was just ashes. Buildings were in ashes. They were just big piles on the ground.

[Jeremiah Kroll]

He landed near ground zero. And like everyone there, struggled to make sense of what had just happened.

[Scott Decker]

The morning of 12th September, things were a little up in the air. I don't think any of us knew what to really expect.

[Jeremiah Kroll]

But Decker isn't looking at the scene the same way as most first responders. In fact, he's there for something else. What the public didn't know at the time is that there was another looming threat.

[Scott Decker]

We expected a secondary attack. There was rumors of a biological attack. The country took steps to get ready for it. Unbeknownst to the public, there was reliable.

[Jeremiah Kroll]

Intelligence from the weeks right before 911 that Al Qaeda was planning a different kind of attack. In addition to September 11, one involving the release of biotoxins into the air.

[Scott Decker]

A second attack was going to become at any moment.

[Jeremiah Kroll]

Decker was part of the FBI's new hazardous response team. So while everyone else was looking at the wreckage, he was on high alert, searching for signs like unusual illnesses, that this second attack, this time biological, was already underway. What no one knew at the time is that they were looking in the wrong city.

[Scott Decker]

The Florida man has contracted a very rare and potentially deadly form of anthrax. As all Americans know, recent weeks have brought a second wave of terrorist attacks upon our country. The deadly bacteria have now turned up in the American capital.

[Jeremiah Kroll]

Deadly anthrax spores sent through the U.S. mail. One of the most lethal weapons of all time comes from an almost indestructible bacteria called anthrax. And in the fall of 2001, envelopes laced with powdered anthrax started showing up in the mail. The latest letter to have been discovered is thought to contain literally billions of spores.

[News Anchor]

The letters sent to NBC and the.

[Scott Decker]

New York Post were the same.

[Jeremiah Kroll]

There's a warning.

[News Anchor]

Take penicillin now.

[Jeremiah Kroll]

You cannot stop us.

[News Anchor]

We have this anthrax.

[Jeremiah Kroll]

Die now.

[News Anchor]

Are you afraid?

[Jeremiah Kroll]

The anthrax attacks created chaos. The US Capitol and the Supreme Court were contaminated and shut down. Thousands of buildings across the country were evacuated and innocent people died just from opening their mail.

[Scott Decker]

The US House of Representatives is closing offices today until 2. What is perhaps worrying Americans the most is that they still have no idea who is behind these attacks.

[Jeremiah Kroll]

What's weird is that almost 25 years later, most Americans still have no idea who is behind these attacks. Anthrax was on the nightly news for months. And then it's like the story just disappeared. I've talked to hundreds of people about it, and no one, it seems, remembers what happened with this case. Who mailed those letters, do you know? My name is Jeremiah Kroll. I'm a documentary filmmaker. And I was living and working in New York when all this happened. In those weeks right after 9 11. I remember the stillness of the streets and the collective sense of raw outrage and sadness in the city. And then anthrax. I felt the fear those letters created, the terrifying way they just kept coming one after another.

[Scott Decker]

Another day of germ warfare, and still no sign. The worst case of bioterrorism in this.

[Jeremiah Kroll]

Country is close to being solved almost two decades later. When the pandemic hit, I felt that same sense of unpredictable terror in the air. It reminded me of the anthrax story, and I wondered, whatever happened with that. So my team and I started digging into it. We tracked down people who were involved, either affected by the attacks or part of the investigation. FBI agents, victims, wrongly accused suspects. And the stories they shared, many for the first time, surprised me. They painted a picture of these events and their aftermath that revealed how, at its core, this was all so personal. Like stories about investigative mistakes right from the start, about civil liberties trampled and about lives destroyed. They broke the front door and there.

[Scott Decker]

Are agents with Uzis and moon suits.

[Jeremiah Kroll]

It's one of the most devastating things that's ever happened to me. It'll follow me forever.

[Scott Decker]

I want to look my fellow Americans directly in the eye and declared to them, I am not the anthrax killer.

[Jeremiah Kroll]

And even after all of that, after the seven year odyssey, the FBI went on to try to solve this case. Some people still wonder if the FBI got it right.

[Dr. Paul Keim]

I would not consider the case to be closed. In my mind, it certainly is not solved.

[Scott Decker]

I believe there are others who can be charged with murder.

[Jeremiah Kroll]

This is a story about people who have to look at chaos and try to make sense of it while it's still happening and how hard it is to get that right.

[Scott Decker]

The worst thing that can happen to an FBI agent working a criminal investigation is to solve it in your mind before you really have the evidence.

[Jeremiah Kroll]

It's about the stories we tell ourselves and the price we pay when we tell the wrong ones. We're going to go inside one of the largest FBI investigations in history to figure out why we all lost track of this case and to explore the aftershocks we still feel today. From Wolf Entertainment, this is the hunt for the anthrax killer. Episode One isolated incident. I want to go back to the beginning of this story, to a time when most Americans never gave much thought to face masks or deadly particles in the air. It's October 2, 2001, three weeks after the attacks of 9 11, and we're in suburban Florida. It's the middle of the night, and a man named Robert Stevens wakes up feeling sick. He has chills and a fever. Robert Stevens is 63. He's a newspaper photo editor who lives in Lantana, Florida. That's a coastal town about an hour north of Miami. He's raised a few kids and is getting close to retirement. But when he wakes up that night, he feels disoriented, dizzy, and things seem to be getting worse. His wife Maureen is worried.

[News Anchor]

She found him awake in the bathroom, vomiting over the toilet bowl, confused.

[Jeremiah Kroll]

Dr. Larry Bush was chairman of infectious diseases and chief of staff at the JFK Medical center in West Palm beach, the hospital closest to Robert and Maureen Stevens house.

[News Anchor]

She drove him to the hospital. He walked into JFK emergency room at around 2 in the morning. And after they put him on a ventilator and got a chest radiograph, they sent him for a spinal fluid examination, looking for bacteria.

[Jeremiah Kroll]

Robert's condition gets worse. He goes into a coma. Larry and his team suspect that he has meningitis, an infection that makes the brain swell. So he looks at Robert's spinal fluid.

[News Anchor]

When I look at the microscope, I'm looking to see if I could see what type of bacteria this is, because that's important for how I'm going to treat him.

[Jeremiah Kroll]

In a healthy patient, Larry shouldn't see much of anything.

[News Anchor]

You're lucky if you can see one or two bacteria that help you determine what type of bacterial process this may be. His was overwhelming. I saw an overwhelming amount of pus cells. That's a bad sign. That means there's havoc going on in your nervous system.

[Jeremiah Kroll]

These bacteria suggest a cause of infection that shocks Larry.

[News Anchor]

They almost never, ever cause spinal fluid infection, meningitis. But one does. Anthrax.

[Jeremiah Kroll]

Larry can't get his head around this. Most of us are now familiar with anthrax, largely because of this case. But back then, in 2001, this was nuts. Most people didn't think about anthrax at all. And for doctors, it was something you read about in textbooks, not something you expected to see in a patient.

[News Anchor]

There were a lot of things going through my mind. There's nothing else that explains it, but.

[Jeremiah Kroll]

It just doesn't make sense. Anthrax is a natural bacteria that usually only infects livestock, cattle tend to catch it in dry rural areas. They eat or breathe in anthrax cells called spores while they're grazing. So it's not like a guy in suburban Florida is going to just accidentally breathe this stuff in while going about his life. And if he did, somehow, he'd be the first person in the entire US in almost 25 years. And that person had gotten it from inhaling anthrax spores off of wool shipped over from Pakistan. Larry runs more tests.

[News Anchor]

He had an overwhelming amount of bacteria. But what struck me was the shape and the color of these bacteria.

[Jeremiah Kroll]

He sees tiny blue stained bacterial rectangles all in a line. Imagine looking down on a train from high in the air.

[News Anchor]

I'm an infectious disease person. I lecture, I write on infectious diseases. I look at bacteria under a microscope every day. I knew what I was looking at in retrospect.

[Jeremiah Kroll]

Now, knowing how everything would play out. This is the moment that it all began right here. For the first time in 25 years, it seems that someone in America has anthrax in their lungs.

[News Anchor]

I'm convinced this is anthrax. I don't have 100% proof.

[Jeremiah Kroll]

Imagine you're him right now. You're the chief of staff for the whole hospital and you're very sure that what you see is one thing, but that one thing is so rare and so deadly that when you tell people about it, they'll either not believe you or. Or panic.

[News Anchor]

My fear was creating chaos in the hospital.

[Jeremiah Kroll]

Chaos not just in his hospital, but also likely all of Florida and probably the nation. After 9 11, the whole country was bracing for another attack. Larry's afraid that this could be it.

[News Anchor]

He can't be the only one exposed. That's my concern. My fear was missing bioterrorism. And being the person who could blow.

[Jeremiah Kroll]

To whistle, he has to risk creating that chaos. So he does. Larry calls Dr. Jean Malecki, a friend and colleague who is the health director for all of Palm Beach County. But she was busy at that moment.

[Dr. Jean Malecki]

I was giving an actual seminar on bioterrorism at the time the phone call came in. And so we were in the middle of that when my secretary rushed over to hand me a note from Dr. Bush. So I left the seminar and went to my office and I got the call from Larry and he said, oh, Gene, I need to talk to you. I said, make sure your door's closed.

[Jeremiah Kroll]

Larry tells Gene he thinks Robert Stevens has anthrax. They both know more tests need to be done to prove it. So Gene calls up the centers for disease control. But the CDC pushes back. They refuse to believe anyone could catch anthrax in suburban Florida.

[Dr. Jean Malecki]

I was told by the state of Florida, the public health laboratory and the cdc, you don't have enough information. And I said, wait a minute. I have a potential anthrax event occurring in my backyard here. I am the chief health officer here, and you're telling me not to act on this. And that's exactly what they were telling me. And I said, well, too bad. You're getting specimens in the mail. You will have them within 12 hours.

[Jeremiah Kroll]

Despite the CDC's hesitancy and the testing that still needs to be done, Larry and Gene have little doubt that it's anthrax. The real worry on their minds is that this could be the beginning of another attack by Al Qaeda. And what they don't know is that the FBI is worried about another attack, too.

[Scott Decker]

The underlying current among government and scientists was a second wave of attack is coming, and it very well likely be a biological or chemical bomb. Anthrax. At the top of the list is a biological threat agent number one, FBI.

[Jeremiah Kroll]

Special agent Scott Decker, is one of only a few agents to have investigated nearly the entire case. And he's got skills that few other FBI agents have. A PhD in genetics with a postdoc from Harvard. So that's why he's on the FBI's new hazmat team that was deployed at ground zero.

[Scott Decker]

We would be there ready to help in case there was a biological attack, a chemical attack, or even a radiological release.

[Jeremiah Kroll]

And one reason they even had Decker and his team on site is because of something odd that had happened earlier that summer. In August of 2001, weeks before the twin towers fell or anyone got sick in Florida, the FBI uncovered something in Minnesota. And that discovery would ultimately set the stage for the entire anthrax investigation. One of Decker's FBI colleagues was right in the middle of it.

[Colleen Rowley]

The two flight instructor whistleblowers from a suburban flight school had called our office to tell the duty agent that they were very concerned that there was the most suspicious flight student they had ever come across.

[Jeremiah Kroll]

Colleen Rowley was an FBI agent in Minnesota at the time.

[Colleen Rowley]

He was first of all asking questions that would never be asked by a normal flight student who was trying to actually learn how to fly. There were things about, you know, communications with the ground, things like that that had nothing to do with what he said was an ego boosting trip in order to learn how to fly a 747.

[Jeremiah Kroll]

The flight student's name was Zacharias Moussaoui. He was a Muslim French national. When FBI agents interviewed him, they learned his visa had lapsed, so they had him detained on an immigration violation. Agents suspected he was up to something, but they couldn't prove it. And remember, this is all before 9 11. So he's just one strange guy asking strange questions at a flight school. They couldn't even get a search warrant for his computer. Then September 11th happened.

[Colleen Rowley]

The day of 9 11, we got word from the jail that he was kind of jumping up gleefully when the towers were coming down, looking at a television or something.

[Jeremiah Kroll]

Now they get the search warrant and search his computer.

[Colleen Rowley]

The only thing that was eventually found on his laptop was a lot of information about wind and wind directions and how to fly like a crop duster, things like that.

[Jeremiah Kroll]

A crop duster? A crop duster is a small plane used in agriculture to spray pesticides.

[Colleen Rowley]

He initially says, well I was involved in other plots, but not the 911 one. So if he's not involved in the 911 one and he's in a second wave, he actually kind of admitted I was going to be a second wave.

[Jeremiah Kroll]

What he's saying is that he's a member of Al Qaeda and that they were planning a second wave attack. They already know the 911 hijackers were studying at flight schools around the United States. So now agents worry that Moussaoui was part of a bigger plot still to come, that he was studying wind direction and crop dusters because he and maybe the others were planning to spray some kind of poison from the air. With all of this info in mind, President Bush and the Department of Justice take action, hoping to prevent whatever that second wave might be.

[Scott Decker]

Yesterday the FBI issued a nationwide alert based on information they received indicating the possibility of attacks using crop dusting aircraft.

[Jeremiah Kroll]

They ground all crop dusters across the country. That solves the immediate problem, but they still have a larger issue. Are there other extremist pilots out there waiting to launch an attack?

[Scott Decker]

Director Mueller and Attorney General Ashcroft gave press conferences announcing the names of all 19 hijackers. The director of the FBI and I.

[Dr. Paul Keim]

Just returned from a memorial service at.

[Scott Decker]

The National Cathedral and wanted to take.

[Dr. Paul Keim]

This time to give you a report.

[Jeremiah Kroll]

Announcing the names was a call for help to the public. If you'd seen something, say something.

[Scott Decker]

The FBI requests that anyone who may.

[Dr. Paul Keim]

Have information about these individuals immediately contact an FBI field office or call the toll free hotline.

[Jeremiah Kroll]

And someone did.

[Dr. Paul Keim]

They didn't want to learn how to land. They just want to learn how to fly.

[Jeremiah Kroll]

Willie Lee is a crop dusting pilot who had an eerily similar story to the one in Minnesota. Suspicious acting men from the Middle east asking unusual questions about planes.

[Scott Decker]

You know, that would tip me off right off the bat.

[Jeremiah Kroll]

But Willie isn't in Minnesota. He's halfway across the country at a different crop dusting business. He'd been flying crop dusting planes for decades. On any given day during his regular job, he'd pack as much as 500 gallons of pesticides into his Air Tractor 502 crop plane. He'd fly incredibly low to the ground to avoid spraying homes and people.

[Scott Decker]

We'd fly two or three feet off the ground whenever we're spraying. It takes some experience to do it.

[Jeremiah Kroll]

But these men didn't sound like they wanted that experience. They were asking about tank capacity and flight distances. It sounded off. So six weeks before September 11, Willie called the police.

[Scott Decker]

I told him, I said, these people, something's up here. I said, these people ask you questions that people don't ask.

[Jeremiah Kroll]

But the police didn't do anything about it. They couldn't really. No one had done anything illegal after 9 11. When Willie saw the names and pictures of the hijackers on television, he knew he'd been right to be suspicious. Because some of the men who'd visited him were the same men who flew the planes into the Twin Towers. In fact, one of them was Mohammed Atta, the chief US operative who directed the attack. Willy and his team called the FBI. This time they listened. So now the FBI has to figure out why were Al Qaeda members in at least two different places around the country trying to learn how to fly crop dusters? And then totally separately, there's the question that Dr. Larry Bush is asking. How does a man in suburban Florida have anthrax? And these two mysteries are about to collide because the airfield that the 911 terrorists visited, Willie's airfield. It's less than an hour from the hospital where Robert Stevens is in a coma. Back in that hospital, Robert Stevens health is deteriorating. And Dr. Bush still doesn't know for certain what he's dealing with.

[News Anchor]

8:00 the next morning, I call Jacksonville Reference Lab and I say, what was the result? And he said to me, I shouldn't tell you that. I said, wow, that's a bold answer. I said, well, there's two things with that answer. I said, first of all, I'm the treating doctor. I'm taking care of this patient. I'm responsible for him. I sent the lab to you. I said, and by you telling me you shouldn't tell me that. You just told me that. He said, I gotta go. I said, where you going? He says, I have to call the people I work for. He hung up.

[Jeremiah Kroll]

The people he works for are high up on the chain. In an instant, the CDC calls the National Department of Health, who calls the White House, who calls the Department of Justice. And now, finally, the FBI learns anthrax is in Florida. Because of his background in science, Agent Scott Decker now knows an anthrax infection shouldn't have happened in Florida. So for the FBI, who'd been worried for weeks about some kind of biological attack, likely from the air, maybe involving crop dusters, if this isn't the work of the same 911 terrorists who they now know took flight lessons at an airfield only an hour away, it's an awful lot of coincidences.

[Scott Decker]

We didn't know if it was an act of terrorism. So that was the first thing we had to do, is prove one way or t'other.

[Jeremiah Kroll]

And in order to do this, prove its terrorism. Decker and the FBI need to know what kind of anthrax this is. Because anthrax comes in strains like the flu. And if they can figure out the strain that might tell agents where or how Stevens got infected.

[Scott Decker]

He had been up in North Carolina when he got sick, visiting his daughter, and they had gone to a state park. There was a thought that he had got infected up there. One of the plants or the bad water or something.

[Jeremiah Kroll]

FBI agents head to the state park to look for any signs that Stevens could have been infected in nature. But the scarier scenario is that the anthrax came from a laboratory. Because if it's from a lab, there's a good chance somebody spread it on purpose. To figure this out, the FBI knows exactly who to turn to.

[Scott Decker]

We agreed to call up Dr. Paul Keim in Arizona, Northern Arizona University. He was the unquestioned expert in the country.

[Dr. Paul Keim]

Yeah, so I was doing my normal college professor stuff at the beginning of a fall semester here in Flagstaff, Arizona, and out of the blue, acquaintance of mine from the FBI called me up and said, hey, we have an unusual case of anthrax down in Florida.

[Jeremiah Kroll]

Dr. Paul Keim hoped to find the source of the anthrax in a biological database he'd been creating for decades.

[Dr. Paul Keim]

For the last 30 years, I've been involved in trying to develop DNA methods for precisely identifying strains of dangerous pathogens so that we can identify where they came from, link them together with outbreaks, and in particular, how they're related to biological weapons.

[Jeremiah Kroll]

So as Robert Stephens is lying in a coma. Investigators put a sample of his spinal fluid on a private jet and fly it halfway across the country directly to Paul.

[Dr. Paul Keim]

And so it was like, wow, it felt like all the blood was leaving my body at that point, because it's like, this isn't an academic exercise anymore. This is the real thing. So after I hung up, I quickly went around and found all the anthrax DNA fingerprinting people. I told them I expected to have the anthrax back in the lab by about 8:00 in the evening. So I said, you know, take care of whatever you need, but be back here around 8 o'clock and be prepared to start doing the analysis.

[Jeremiah Kroll]

A few hours later, Paul gets in his truck and heads to the small local airport in Flagstaff. He doesn't know quite what to expect.

[Dr. Paul Keim]

The general aviation guy just went and opened up the gate and let me drive out on the tarmac, you know, and Gulf Stream's a pretty impressive plane. And so it landed right around sunset. Then this woman, this blonde woman, came walking down the stairs with a box. And as she stepped onto the tarmac, you know, all I could think about was the movie Casablanca where Humphrey Bogart is on the tarmac with Ingrid Bergman. And I thought that'd make me Humphrey Bogart. And then I kind of slapped my face and said, get your head back in the game.

[Jeremiah Kroll]

You know, Paul may not be in a Hollywood movie right now, but in a way he is a detective. And in this very moment, the fate of American biosecurity is quite literally in his hands. So he takes that package and drives it back to his lab. And there he goes into the biosafety suite and opens the box.

[Dr. Paul Keim]

And there's a box, you know, like, I know, 18 inches by 18 inches by 18 inches, a cardboard box. And inside of it was a styrofoam pack and then a crush proof pack.

[Jeremiah Kroll]

And inside that is a vial with the spores found in Robert Stevens spinal fluid.

[Dr. Paul Keim]

When you're looking at it by eye on a culture, it's kind of this white, creamy stuff, kind of like mayonnaise smeared on top of jello. We knew for sure it was anthrax because it had a DNA fingerprint pattern that was very consistent with Bacillus anthracis.

[Jeremiah Kroll]

It's anthrax 100%. Once Paul knows that, he needs to figure out what strain it is.

[Dr. Paul Keim]

And my laboratory had been developing DNA fingerprinting methods to identify the different strains from around the world. And if it was a laboratory strain, this wasn't an accident. In the wake of 9 11, Paul.

[Jeremiah Kroll]

And his team work through the night. By morning, they have an answer.

[Dr. Paul Keim]

It was a laboratory strain, you know, and so how does a laboratory strain end up infecting a gentleman in Florida?

[Jeremiah Kroll]

Think about this. Here's a college science professor, an expert in theoretical bioterrorism, and now he's seeing right up close anthrax from what appears to be an actual bioterrorist.

[Dr. Paul Keim]

Instantly we knew that this was a biological weapons event because it had to be an intentional act. And in the wake of 9 11, al Qaeda was the number one suspect.

[Jeremiah Kroll]

Paul's lab is the only place in the world that now knows the very threat weighing on Agent Scott Decker and the FBI is the real deal.

[Dr. Paul Keim]

At that point, if there were any doubts that this was a bioterrorism event, they were gone.

[Jeremiah Kroll]

For the moment, the story hasn't spread to the media. Paul Keim, Scott Decker and the FBI have only a short window to try to get answers before the bad news spreads. And they're all wondering the same thing. Was it the 911 hijackers who deployed this anthrax? Gene Malecki, the health director in Florida, worries about that too.

[Dr. Jean Malecki]

In Palm beach county, we use crop dusters all the time. They go up and down all the time, spraying our vegetables and our fruits.

[Jeremiah Kroll]

If there was an aerial attack, is it possible the 911 hijackers or people working with them had dropped anthrax in an area that included Robert Stephens backyard? Is that how it ended up in his system? Steven's home was less than a mile from an airstrip, so his house could have easily been in the path of travel.

[Dr. Jean Malecki]

My focus was to go to the home to speak to everybody there, to take samples, to investigate the entire outside of the home, inside the home to look at potential sources for anthrax.

[Jeremiah Kroll]

Jean takes a biohazard crew to scour the property from top to bottom.

[Dr. Jean Malecki]

The home itself was a three bedrooms, probably two baths, nice little kitchen and living room.

[Jeremiah Kroll]

The powder is so fine that if it was sprayed from the sky, it could be anywhere.

[Dr. Jean Malecki]

In the backyard, they had lots of plants and lots of trees. We looked for any type of white powder, substances that could have been in the trees or on the ground. I remember distinctly bending down and taking samples off of various bushes that were in the backyard.

[Jeremiah Kroll]

On the surface, nothing looks suspicious. There's no obvious white powder anywhere. But Jean sends samples. She's taken to her lab. She then heads back to the hospital to check on Robert Stevens and discovers a deadly disease putting a Lantana man in the hospital. The story was out. Mohammed Atta, who was the lead terrorist on board one of the flights that crashed into the World Trade center, apparently took flight lessons in Palm beach county at a flight school. Anthrax can enter the body in three ways. It can be swallowed, seeped through, cuts in the skin, and the most deadly way, inhale. State and federal health officials hurry to put together press conferences to address everyone's concerns. This individual is being cared for by a very well trained and expert team of physicians from within the hospital in Palm Beach. As one of those well trained physicians, Dr. Larry Bush is called upon to answer some tough questions.

[News Anchor]

The difficult part for me in that press conference was Maureen Stevens was sitting in the front and they said to me, is Bob Stevens going to die?

[Jeremiah Kroll]

Larry knows that historically inhalation anthrax is likely fatal, but he's conflicted about sharing the worst case scenario.

[News Anchor]

But I'm looking at Maureen Stevens and I said, well, you know, he's seriously ill. He's on the right medication and we have hope that he could survive.

[Jeremiah Kroll]

Meanwhile, the press keep on with their questions and the CDC seems entirely focused on hitting the same reassuring note over and over again.

[Scott Decker]

I want to stress two things. First of all, that this is an isolated case, and second, that this is not contagious.

[Jeremiah Kroll]

This is a very serious illness. But once again, it's an isolated case.

[Scott Decker]

But I do want to stress again.

[Jeremiah Kroll]

I want to reiterate, this is an isolated case.

[Scott Decker]

This is an isolated case.

[Jeremiah Kroll]

The disease is not contagious. If the hope was to keep people calm, to reassure the media that this situation was nothing to worry about, it didn't work.

[Scott Decker]

The Centers for Disease Control has just confirmed the diagnosis of anthrax in a patient in a Florida hospital.

[News Anchor]

There's more media in the area because things are leaking out than you can imagine. The parking lot's full of every type of media.

[Jeremiah Kroll]

There is the chaos Dr. Larry Bush was afraid of is here.

[Scott Decker]

All this coming just a day after the FBI was warned Americans that another terrorist attack could be imminent.

[News Anchor]

The hospital is going crazy. People are calling the hospital and want their loved ones transferred because we have anthrax in the hospital.

[Scott Decker]

The Florida man has contracted a very rare and potentially deadly form of anthrax.

[News Anchor]

The outside of the hospital was one of those things like you see when, you know, somebody's coming out of a courthouse and everybody's rushing in with a microphone to get some type of sound bite. It was, you know, really chaotic.

[Jeremiah Kroll]

Everyone is now watching Larry's team closely to understand what this one case of anthrax might mean for the rest of the world. And the news he has is not looking good.

[News Anchor]

Bob Stevens is in the icu. He's not doing well.

[Jeremiah Kroll]

Robert Stevens health is failing quickly, and Larry fears the worst. With the story out in the world, panic is going to grow. And the public wouldn't be wrong to worry. It seems Robert Stevens may be patient zero of a colossal new attack. Agent Decker and the FBI now face what could be the largest bioterror threat in American history. So the question on their minds is, if Al Qaeda does have anthrax, what will they do with it next?

[Scott Decker]

The worst case is if somebody had succeeded in making a large amount. It's possible hundreds could die. Definitely hundreds, possibly thousands.

[Jeremiah Kroll]

But it seems that agents are closing in on their suspects fast. The confirmation of a plan for a second wave attack, the pilots learning about crop dusters, the airstrip near Steven's house. It's all adding up. The FBI just needs a little hard evidence, a link that proves who did this so they can stop more deaths.

[News Anchor]

I get a call to come down and see this woman, and I said to the emergency room doctor, you know, this is getting a little overwhelming. You're calling me for every cough that's walking in there. I said, why this one? They said, this woman's got an interesting story.

[Jeremiah Kroll]

But of course, it's not going to be that easy. The information they're about to get will send the FBI down a rabbit hole of false suspects, shocking twists and damning revelations, including a liar in their midst. This season on Aftermath, the hunt for the anthrax killer. No witnesses. No fingerprints or personal DNA.

[Dr. Paul Keim]

And then there's another case. And then another and another.

[Colleen Rowley]

There was such enthusiasm over a conspiracy.

[Jeremiah Kroll]

Theory that had no basis.

[Scott Decker]

I felt betrayed.

[Jeremiah Kroll]

American and coalition forces are in the early stages of military operations to disarm Iraq.

[Scott Decker]

That Saddam Hussein could have produced 25,000.

[News Anchor]

Liters of this deadly material. Do you think they're going to submit evidence that implicates them?

[Scott Decker]

This is United States.

[Jeremiah Kroll]

Half of the FBI field office from Washington is at your home.

[Scott Decker]

This is not a joke. What is everybody?

[News Anchor]

A dead man walking?

[Narrator]

Be sure to follow. Aftermath Hunt for the Anthrax Killer available now. Wherever you get your podcasts.