
There is a man serving a life sentence in a Florida prison for his part in the 1989 murder of a 29-year-old pregnant woman named Donna Callahan. Two brothers were ultimately convicted for her abduction – and each of them pointed to the other as the ultimate preparator. But only one of them would go on to confess to over a dozen other murders. That man is now considered, by some, to be one of the deadliest killers on Florida’s Gulf Coast. And if his original confessions are to be believed, then not one, but two Fort Walton Beach cases could be closed. Right now, one detective is making it his mission to find out once and for all: Can he prove Mark Riebe is the serial killer everyone thinks he is? And was he–or someone else entirely–responsible for the murders of Ronda Taylor and Bonnie Ryther?
Loading summary
A
Hi everyone. Ashley here with some exciting news. The Deck will not only land right here in your feed for you to listen to every week, but now we are also on camera for you to watch on YouTube. Now you can see the cards, the case files, and the people behind the coldest cases as I share these stories with you. So no matter where you get your podcasts, whether you prefer to listen to watch or maybe both, I will be there with stories you need to hear. Join me for the Deck on YouTube. Subscribe to Audio Chuck Investigates on YouTube today. Our cards this week are Rhonda Taylor, the king of clubs from Florida, and Bonnie Reither, the nine of diamonds from Florida. There is a man serving life in a Florida prison for his part in the 1989 murder of a 29 year old pregnant woman named Donna Callahan. Two brothers were ultimately convicted for her abduction and each of them pointed to the other as the ultimate perpetrator in her death. But only one of them would go on to confess to over a dozen other murders. And that man, Mark Reby, is now considered by some to be one of the deadliest serial killers on Florida's Gulf Coast. And if his original confession is to be believed, then he not one, but two Fort Walton beach cases could be closed. So one detective is making it his mission to find out once and for all, can he prove Mark Reby is the serial killer everyone thinks he is? I'm Ashley Flowers and this is the Deck. In 1998, an agent from the Florida Department of Law Enforcement went to visit an inmate at the Union Correctional Institution in in Rayford, Florida. That man's name was Mark Riebe, and at that point, he'd been in prison for more than five months for murdering a pregnant woman named Donna Callahan. But the FDLE wasn't up there to talk to him about that. Mark had sent a letter to the FDLE agent requesting a meeting to talk about the 12 other murders he said he'd committed. What followed was a chilling recitation as Mark rattled off descriptions of 13 victims along with how they were killed. Some vague, others specific. Like a woman in her condo in Destin beaten with a crowbar. An exotic dancer in Orlando strangled. A young white woman in Fort Walton beach strangled. And while many on his list were described simply as women or girls, some confessions included names like Donna Callahan, the pregnant woman who he was incarcerated for killing at a convenience store in Gulf Breeze. She was strangled. He also listed Pamela Ray in Panama City, strangled. And number 11 on his list, 23 year old Rhonda Taylor, who He confessed to stabbing multiple times with a knife in Fort Walton beach back in 1990. That last name, that's partially what gave this confession legitimacy, because a Rhonda Taylor was found stabbed to death in that exact location mentioned in the confession during that exact year. But their best lead fizzled out quickly because a few months after that first meeting with fdle, Mark backtracked. He recanted the whole thing. And any investigation into a man that could have been one of the deadliest killers on Florida's Gulf coast went up in smoke. But recently, one detective who's been working on Rhonda's case has revisited that old confession, wondering if the answer has been there this whole time, just waiting for the right person to come along and unearth the clue.
B
So my name is Detective Michael Wilson. I'm a detective with the Criminal Investigative Unit here at the Fort Walton Beach Police Department. Fort Walton Beach, Florida. I've always wanted to become an investigator, right? Going back to probably my mother, who was really into true crime and introduced me, didn't really introduce me. She would check out a lot of books from the library that were mysteries and true crime related, and I'd squirrel them away and she'd get mad at me. But I'd bring them to my room and read them. And I was always fascinated. And what always particularly fascinated me was the role of the detectives in those stories.
A
Detective Wilson took on Rhonda's case two years ago, and while other detectives had come before him, they left behind years of unanswered questions and mountains of paperwork.
B
So if you can imagine, like, I became an investigator, you handle these cold cases, it's like, okay, you know, you sort of look and where did somebody leave off? Okay, could I see the case file? Will we have to go back into storage? And you get a box covered in dust, you know, and you open it and it's like a time capsule.
A
Let me share with you what Detective Wilson found in, in this time capsule about Rhonda Taylor. On Saturday, July 7, 1990, the weekend after Independence Day, Florida's beaches were crowded with vacationers soaking up the summer sun. It was about noon when a call came into the Fort Walton Beach Police Department. Less than a mile away on Tupelo Avenue, a man walking past a parked silver Buick Opal noticed something unusual in the backseat. What he at first thought was a blow up doll was actually a woman. Rhonda, crumpled up naked in the backseat of her own car, deceased from 10 stab wounds to her chest and neck.
B
The car was towed in basically so it could be more thoroughly examined. So numerous pieces of evidence were taken from the car. But, I mean, there was no smoking gun. There was no, like, okay, here's the ID of the person that was with her, or here's a fingerprint or anything like that. There was a lot of blood, basically, and you could tell that something had happened to her outside the car, basically. And then she was placed back in the car, the car was driven to where it was found, and then she was left there.
A
But it was where her car was left that would leave investigators scratching their heads, because basically, it was right smack dab in the middle of town. Why would someone create a crime scene where it could so easily be found? Who would be that brazen? Back in the day, police started with the usual suspects, including Rhonda's on again, off again boyfriend, Steve. Around the time of her murder, Rhonda and Steve's communication was mainly through letters, which were sitting on Detective Wilson's desk when our reporter Annie Roderick Jones, visited. Rhonda's writing itself was a reminder of just how young she was.
B
What gets me is seeing her handwriting. Yeah, yeah. Really sad. It's just got that, like, high school girl handwriting. I know. And you could see she was struggling, you know?
C
Yeah, you could. And that she wanted to, you know, to get better.
B
Yeah.
A
Rhonda was battling a substance use disorder from rehab. She wrote to her boyfriend in loopy bubbly cursive. And in those letters, her hope came through. Clearly, she wanted to get well. I mean, Steve also struggled with substance use disorder and probably understood what Rhonda was going through. But when it came to Steve, Detective Wilson said that he didn't remain a person of interest for very long.
B
He was interviewed, and he was exonerated pretty early on. I think it was one of those things where he was struggling with his own addictions. And so they were kind of trying to get clean. You know, both of them were trying to get clean. And so he had an alibi, and he was exonerated.
A
Early on Fort Walton beach, detectives also interviewed a man that Rhonda was supposed to have a date with on the night of her murder. Although Detective Wilson told our reporter that Rhonda actually stood that guy up, and she was seen by other witnesses during and after the time of that date. In fact, Detective Wilson said that about a half a dozen witnesses said that they saw her on the evening of the sixth with two different men that night, like, all three of them together. And apparently they were looking for drugs. He also said that her Known drug use caused a lot of speculation on the streets.
B
So after she's found murdered, a lot of these people started to come up with all their theories. She was taken here. It was because she owed this guy money. It's because she ripped this guy off. It's because she. You know, this book is full of those theories.
A
For more than eight long years, law enforcement really had nothing other than those rumors and theories. That is, they never found a murder weapon. They never got prints or anything from her car. And although Rhonda was found nude, she hadn't been sexually assaulted, so there weren't any foreign biologics that were found during her autopsy. They were stuck.
B
And then we have the confession, which just changed everything. There was evidence in the house, and.
A
They would not listen to me.
D
The Proof podcast is back with a new case and a new season. And this time, the stakes are higher than ever before.
E
The letter from the doctor said, I have six months or less to live. I'm scared shiftless right now.
D
A dying man is serving a life sentence for a murder he says he didn't commit.
A
Did you ever question if they got the right person?
C
I don't think I believed it at the time. I don't think I believe it now.
A
I'm scared to be sitting here in this damn chair talking about this shit.
E
How many other cold cases are gonna come forward and go, hey, man, we need to look at my shit because I didn't do it. How many more do we have?
D
You can listen now to season three of Prove, wherever you get your podcasts and follow along with us as we reinvestigate the murder at the bike shop.
B
Everything I tell you is the truth. I'm not bullshitting one way or the other. I hope I don't bring a ton of shit down on me. I really do.
A
Even when Mark Rebe said that he didn't kill Rhonda, the details in his confession felt entirely too spot on. I mean, they were details it seemed that only Rhonda's killer would know. First of all, Rhonda Taylor was one of the few people on Mark's list of victims who he noted by name. And that's because, unlike some of the others on his list, investigators believe that Mark actually knew Rhonda.
B
I think it was his. A relative of his was in rehab at the same time she was in rehab. So he had known her from before. And so they knew each other. They see each other. You want to go find some rock? Okay. Because he was into that at the time, too.
A
That's what Mark said they were doing together that day when he originally confessed to the FDLE agent. And one of those facts that seemed like he wouldn't know unless he was there. He told the agent that he and Rhonda had picked up another guy, which would explain why so many witnesses saw her with two men.
B
The three of them go to a place called Ranger Trail Road, smoke the crack. He basically says that she went to perform a sex act with the guy. I think he doesn't say this, but from what he says is that she said something to him to piss him off. And supposedly that's his M.O. is that, like, a woman will say something to him, and it'll set him off, and he goes into a murderous rage. And according to him, like, I just black out, you know, I just don't know what happens. And so he actually admitted to stabbing her with a buck knife, which would be consistent with her wounds. He stated, he said, where he threw the buck knife away off of a bridge, which is nearby here.
A
Rhonda and her car were found near a nursing home not too far from that bridge. That's actually where the 911 call to police came from. Well, Detective Wilson told our reporter Annie, that the nursing home, or as he calls it, a convalescent center, turned out to be more significant.
B
Standing where that car was, you can see the convalescent center. He had worked at that convalescent center. And the night the. The night she was murdered, his wife was working there, so it would make sense. It's like, I have to get someplace I can walk to. I got to dump this car and get a change of clothes or something and get out of here. Right.
C
Did he admit all of those things that he walked to the convalescent home?
B
Yes.
C
Okay. And that's when his wife.
B
He doesn't implicate his wife, though. He just said he went back there and got clothes and that he dumped his clothes in a dumpster nearby, which was checked, but it was already dumped.
A
I think to Detective Wilson, the details of this confession are all specific and believable. And if Mark is to be believed in regards to Rhonda, then it would make a lot of sense to look at him for another Fort Walton beach case.
B
I was assigned Bonnie Reither's case because they thought it might be linked to Rhonda Taylor's homicide.
A
Detective Wilson doesn't have nearly the amount of information on Bonnie's case that he has on Rhonda's, mostly because it's older. While Rhonda was killed in 1990. Bonnie's murder dates all the way back to 1978. But he does know that Bonnie was last seen at a place that is now long gone called the Continental Club. She had had some beers there and then left by herself, and then nothing. Till her boyfriend reported her missing. And her employer at the Holiday Inn in Okaloosa island said that the 27 year old didn't show up for work. Six days later, an abandoned vehicle was reported and it all finally clicked.
B
And so the detectives working at the time are getting these missing persons reports. They realize, hey, her car is seen at Ferry Park. So they go to Ferry park and turn up her car sitting there.
A
Not long after, investigators found Bonnie's car and her remains nearby.
C
Do you have in the report who found them? Who found her?
B
It was actually, yeah, actually I do. Hold on. It's on 411. The two detectives were doing a follow up on a missing person, and they discovered the partially decomposed body of an unidentified white female. It's partially covered with dirt and sand and underbrush. The body was located behind the Ferry Park Recreation center in Fort Walton Beach. From what I saw from the crime scene photos, it was like a shallow grave, partially because it had rained. So the rain had uncovered some of the body. I think on her left side you could see like an arm and stuff like that. The final stages of the exhumation continued under the direct supervision of the medical examiner. Exhumation disclosed the body of a white female, partially decomposed with black hair, clothed and torn denim pants pulled down to the knees, white or light color underpants rolled down to the upper thighs. No shoes and what appeared to be a green upper body garment, which is a description of the clothing she was wearing. The last clothing she was wearing. A canvas of the area was conducted. No additional physical evidence was found. So the car became the main piece of physical evidence. Right. And the contents of the car is what we still have. Including the seats? Not the seats, but the seat covers.
C
So what is that telling them about her? Like the way she was found? Do they know whether she was sexually assaulted?
B
I don't think so. I don't think she was. So the medical examiner determined that the victim had been severely beaten to death, and her death was due to either the beating or the strangulation. But I don't think I ever found anything where they said that they believed she was sexually assaulted. But, I mean, the way she was found suggests that she might have been.
A
You know, Additional reports tell us that Bonnie's boyfriend was Cleared early on. And no one in her life seemed even close to being a suspect. So, like Rhonda's case, law enforcement was at a massive standstill that stretched on for decades until Mark Reby's statement. Now, unlike Rhonda, he never identified Bonnie by name. What he did say was that one of the murders he committed was that of a young white woman in Fort Walton Beach. He specifically said that he had strangled her in 1978. This would have been one of, if not his first victim when he was only 17. Like, vague description, check location, check timeline, check. And there was one very specific piece of evidence that stood out to Detective Wilson. In addition to unsmoked cigarettes found inside Bonnie's car, investigators also collected some beer cans right by where her body was found. Specifically, Natty.
B
Like Tall Boys.
C
Tall Boys. Okay, so that's specific.
B
That was his beer of choice.
C
Did he drink the Tall Boys?
A
Yes.
B
Specifically.
A
There was evidence in the house, and they would not listen to me.
D
The Proof podcast is back with a new case and a new season. And this time, the stakes are higher than ever before.
E
The letter from the doctor said, I have six months or less to live. I'm scared shitless right now.
D
A dying man is serving a life sentence for a murder he says he didn't commit.
A
Did you ever question if they got the right person?
C
I don't think I believed it at the time. I don't think I believe it now.
A
I'm scared to be sitting here in this damn chair talking about this shit.
E
How many other cold cases were gonna come forward and go, hey, man, we need to look at my shit because I didn't do it. How many more do we have?
D
You can listen now to season three of Proof, wherever you get your podcasts and follow along with us as we reinvestigate the murder at the bike shop.
B
Everything I tell you is the truth. I'm not bullshitting one way or the other. I hope I don't bring a ton of shit down on me. I really do.
A
Even though investigators back in 1998 made the connections between Mark and Bonnie, Mark and Rhonda, they never had anything concrete putting Mark Reby at either scene just as confessions. Which is why when he took it back, they were kind of screwed. Over the years, as technology advanced, Fort Walton detectives tried testing what little physical evidence they had, like those Natty Light beer cans from Bonnie Reithers crime scene. But those hadn't been tested since 2008. And back then, they yielded nothing.
C
Do you think that finding the evidence from this Say it ties to Mark. Does that help you in the Rhonda case or vice versa?
B
Absolutely. How so? I think if it would tie to him, it would reinforce the idea that his confession was accurate.
A
That confession was sitting on Detective Wilson's desk when our reporter interviewed him. It listed out the women one by one. So if Mark Reby was able to pinpoint these names and dates and locations, why recant? Mark told Detective Wilson that the reason he confessed was in order to protect somebody. In an interview with Piers Morgan, it seems that somebody was his son. And Mark basically told Detective Wilson that the agent didn't hold up his end of the bargain for said protection, and that's why he recanted. Our reporter tried reaching out to the FDLE agent by email, phone, and Facebook, but we haven't heard any response. Detective Michael Wilson told our reporter that there could be another reason as to why Mark took it all back.
B
This is Florida. You know, a murder is one thing. It's terrible. But if you get convicted of murdering multiple people, the chances of the death penalty are pretty high. Yeah.
C
So I guess I'm just, like, wrapping my head around, let's say, if it's even a day later, he recants, like, why wasn't he arrested in that time? If these things are kind of matching.
B
Up, I still have to work the case. Like, the confession is great, right? That's, like, good. That sounds plausible. Still have to prove it, right? We still have to prove it with either hard evidence, witness testimony, or something. I can't just go on the confession alone. Right. Because that's not going to be enough. Because, you know, you say, well, here's a confession. Jerry, he confessed. What is this defense going to say? He recanted the confession, he was under stress or something. They're going to say he's whatever, you know, but if you have that in addition to something else, then you might have something there. Right.
A
This is formally known in court as corpus delicti, which is Latin for body of the crime, meaning that the state needs evidence beyond just a confession to build a case, especially when the person who confessed has no ties to the crime. So that's what Detective Wilson has been working on. He resubmitted those Natty Lite cans, and he is going through evidence logs to see what else he has to work with. He's already identified Bonnie's car upholstery as something that he plans to test, too.
B
You see some things like, I don't know if this was submitted at all. This was submitted in 2006. You know, it's like the evidence is all in a box. So my thing was just I talked to Apdelia, I talked to her lab, and they said, just go ahead and start sending us stuff. It doesn't matter if it was tested already or not. We'll retest it. Yeah. So that's where I started, and that's what I'm doing.
A
Our reporter Annie, reached out to Mark Riebe, who is currently serving a life sentence in Florida. He denied our request for an interview in person or by phone, and he told her via email that he lost trust in the media after that contentious interview with Piers Morgan. But after a lot of back and forth, he did send this. Hi, Annie, I've received your email with your questions, and I actually started to write and tell you I have already answered all those questions on the interview with Piers Morgan, but instead, I'm going to answer with this statement. No, I had absolutely nothing to do with Rhonda's or Bonnie's cases. In fact, I am not responsible for any of the cases I've been accused of. And I know Detective Wilson, who is handling Rhonda's and Bonnie's cases, has sent in more evidence to be tested for DNA. It is my hope that he will get the evidence that will lead him to the ones responsible for those cases. If so, that will clearly prove that I had nothing to do with those cases. Now, I understand this isn't the way you may have wanted me to answer those questions, but I'm hoping this way my words may not be twisted or misconstrued again. I'm just trying to protect my side. Respectfully, Mark. So if Mark Reby didn't kill Rhonda Taylor or Bonnie Reither, who did? And what do we make of the second person who was supposedly with Mark when Rhonda died? Detective Wilson said in Mark's recanted confession that this second man they picked up witnessed the murder, even tried to intervene, but he was apparently injured in the process. That second person is Detective Wilson's Hail Mary. Now, he didn't want to go into detail about what steps he's taking next involving this other person because this is an active investigation that is unfolding as I speak. But he did assure us that things are moving forward and that he should have an update for us soon. If that's the case, I'll be sure to bring whatever we learn back to you. Detective Wilson has a plan, and he is going to follow the evidence. Even if the evidence plays out the way Mark Rebe told us it would in his statement.
B
You know, I try to stay away from focusing on him and being like, I'm going to make sure I put this guy away. He did it. Because at this point, it's like I'm trying to follow the evidence. Right.
C
Do you have any evidence that doesn't lead you to him at this point?
B
No, because that's the assumption, you know, that he's some kind of big serial killer. But he could be a big liar, too, you know, don't know. You know, I mean, I think it's for an investigator, you have to keep an unbiased approach. You know, there's what you think and what you can prove. That's Police 101. Yeah. You may know something, but it's like, can you prove it? And with him, it's like it's going to have to be DNA or eyewitness testimony. And hopefully, if it is him, it's going to be one of those two things that's going to crack this whole thing. And so if I can just get one or two of those things and we say, look, okay, we got you on this one. Let's go ahead and talk about these other ones you confessed to. And let's quit the bull. Let's tell what really happened.
A
If you know anything about the murders of Rhonda Taylor or Bonnie Reither in Florida's Gulf coast, you can contact Detective Wilson directly at 850-797-2458. You can also call the Emerald Coast Crime Stoppers at 850-863. Tips. The Deck is an Audio Chuck production with theme music by Ryan Lewis. To learn more about the Deck and our advocacy work, visit the deckpodcast.com I think Chuck would approve.
Host: Ashley Flowers
Guests: Detective Michael Wilson (Fort Walton Beach PD), Reporter Annie Roderick Jones
Date: February 11, 2026
This episode delves into two chilling cold cases from Florida's Gulf Coast – the 1990 murder of Rhonda Taylor and the 1978 murder of Bonnie Ryther. Through the lens of the unique "cold case playing cards" program, the episode explores the investigative efforts to link these unsolved homicides to convicted murderer Mark Riebe, who once confessed to a string of murders before recanting. Detective Michael Wilson is at the heart of renewed investigations, meticulously examining old evidence and confessions, while the shadow of Florida’s deadliest alleged serial killer looms large.
With both cases decades cold but brimming with unresolved evidence and unsettling confessions, Detective Wilson forges ahead with a commitment to truth, not assumptions. The episode closes with a direct appeal: anyone with information is encouraged to contact Detective Wilson at 850-797-2458 or the Emerald Coast Crime Stoppers at 850-863-TIPS.
For further details and advocacy information, visit thedeckpodcast.com.