Dateline: True Crime Weekly

Episode Date: October 16, 2025
Host: Blaine Alexander (filling in for Andrea Canning)
Main Stories:

• Mark Sievers and his fight against a death penalty conviction
• Miami model Courtney Clenney accused of murdering her boyfriend
• Donna Adelson’s sentencing in the Dan Markel case
• The new John Wayne Gacy mini-series
• Updates on Ellen Greenberg and Kouri Richins cases

Episode Overview

This week’s Dateline: True Crime Weekly dives deep into several high-profile cases, offering updates and insights from courtrooms around the country. Host Blaine Alexander covers the ongoing legal battle of Mark Sievers, recaps a toxic relationship that turned deadly in Miami, shares details from the emotional sentencing of Donna Adelson, and spotlights a new drama focusing on the often-overlooked victims of serial killer John Wayne Gacy. Expert correspondents and guests provide context, behind-the-scenes details, and thoughtful commentary throughout.

1. Mark Sievers Fights Death Sentence in Florida

Segment starts at 01:40

Background and Case Recap

• Dr. Teresa Sievers, a prominent holistic physician, is found bludgeoned to death in her Bonita Springs, FL home in 2015.
• Her husband, Mark Sievers, was out of state at the time but quickly became the focus of police investigation.
• Mark was convicted in 2019 for orchestrating a murder-for-hire plot and sentenced to death.

Interrogation and Initial Reactions

• Mark's police interview was emotionally fraught: “In this interview room, he's crying, he's hitting him, he's scratching. She had so much to offer the world.”
  (Dennis Murphy, 04:31)
• Mark, distraught, says: “If I came back this wouldn't have happened.”
  (Dennis Murphy, 05:19)

Investigation Breakthroughs

• A call from Missouri links Mark’s longtime friend Wayne Wright to the case.
• Wayne is interrogated and ultimately confesses that Mark solicited him for the murder in exchange for a share of $5 million in insurance.

Defense and Appeal Issues

• Mark’s defense attempts to discredit Wayne as unreliable and possibly motivated by infatuation.

  “There were some text messages…like little pet names and things like that that just—it kind of struck me as this may have been a relationship that, you know, maybe Mr. Wright may have wanted something more out of the relationship.”
  (Blaine Alexander & Dennis Murphy, 08:54-09:16)

• Mark’s original lawyer was not “death certified,” leading to claims of ineffective counsel:

  “The lawyer at the time who argued the case, he was not death certified. So now they're saying maybe this is an appellate issue, that he was not qualified and should not have been in that courtroom.”
  (Dennis Murphy, 07:50)

Notable Evidence

• A post-trial letter from the alleged hitman, Jimmy Rogers, hints at Mark’s possible innocence:

  “Jimmy Rogers comes forward and he says to Mrs. S, you know, your poor boy has been wrongfully accused here. He had nothing to do with it.”
  (Dennis Murphy, 10:03)

Current Status

• An evidentiary hearing is underway to determine if Mark Sievers deserves a new trial due to counsel issues and previously withheld information.

2. Miami Model Courtney Clenney Accused of Murder

Segment starts at 12:35

Case Overview

• On April 3, 2022, Christian Obumseli is fatally stabbed in a luxury Miami apartment; his girlfriend, influencer Courtney Clenney, claims self-defense.

Relationship History

• “This relationship is a classic example of...a toxic relationship. We have videos of the couple arguing, getting physical inside a living room. There's another video of them fighting inside some elevator in their building.”
  (Christian Colon, 13:33)
• Repeated domestic disturbances led the building to consider eviction.

Incident Details

• Clenney says she was attacked and threw a knife at Obumseli from 10 feet away.
• Medical examiner’s findings contest this: the 8-centimeter-deep wound could not be caused by a thrown knife from that distance.

  “According to court documents, Clenney was found with no injuries to prove her claim that she was the one that was attacked.”
  (Christian Colon, 15:47)

New Developments

• Defense is fighting to keep audio evidence (recorded by Obumseli of Clenney berating him) out of the trial.
• Motions are pending regarding bond and admissibility of other evidence.

Context

• “All this evidence gets put together. Prosecutors say, hey, this person has been toxic with the alleged victim in this case. It was clearly for them, second degree murder.”
  (Christian Colon, 16:19)

3. Dateline Roundup

Segment starts at 19:38

Donna Adelson Sentenced in Dan Markel Murder Case

• Donna Adelson, 75, sentenced to life for orchestrating the murder of her former son-in-law, FSU law professor Dan Markel.
• Her husband, Harvey Adelson, delivers an emotional courtroom plea:

  “Donna did not participate in the heinous acts that she was convicted of doing. You are sending an innocent woman to prison. You have taken my wife and you have taken my life as well.”
  (Harvey Adelson, 20:42)

• Donna insists on her innocence:

  “If I had become aware of this plan before Danny was murdered, I would have stopped it.”
  (Donna Adelson, 21:36)

• The judge is unmoved—sentence is mandatory for first-degree murder.

Ellen Greenberg Case Update

• Philadelphia teacher Ellen Greenberg’s death again ruled a suicide after a second medical review, despite 23 stab wounds.

  “The distribution of wounds is admittedly unusual...however, she believes that many of the wounds are what she would call hesitation wounds.”
  (Dr. Lindsay Simon, summarized at 23:43)

Kouri Richins Homicide

• Utah mother and author Kouri Richins remains in jail awaiting trial for allegedly poisoning her husband with fentanyl in hopes of collecting life insurance payout.
• Defense accuses estate executor (husband’s sister) of paying prosecution witnesses; these payments were for expert witness testimony, according to her attorneys.

4. John Wayne Gacy Mini-Series: A Focus on the Victims

Segment starts at 25:17

Series Purpose and Unique Approach

• “Devil in Disguise: John Wayne Gacy,” an NBC drama now streaming on Peacock, shifts the infamous story’s focus to victims, families, and detectives.
• Showrunner Patrick McManus:

  “I want to focus it on the police, I want to focus it on the lawyers, I want to focus on the victims families...I didn't come away from watching the documentary wanting to do it because at the end of the day, the documentary is very focused on John Wayne Gacy.”
  (Patrick McManus, 26:46)

• The series tells “short stories” about victims, without centering Gacy or their murders.

Acting Challenges

• Michael Chernis (Gacy):

  “There are really four Gacy’s: John the contractor, John the politician, John the clown. Then there’s the other guy. To have to embody John Gacy all the time just felt like maybe something I didn’t want to take on just for...mental health reason.”
  (Michael Chernis, 28:13-29:00)

• Gabriel Luna (Detective): Appreciated the chance to portray “the mundanity of heroism” and reflect the real burden carried by law enforcement.

Systemic Issues and Hope

• McManus notes the show spotlights both systemic failures and heroic efforts within Chicago PD:

  “So much of the show is also about the systemic failure of Chicago PD to actually have stopped him...But on the flip side...a group of detectives who were dedicated to ensuring that every last victim was found.”
  (Patrick McManus, 30:09)

• The team hopes the show might help identify still-unknown Gacy victims.

Notable Quotes & Memorable Moments

• Dennis Murphy on early suspicions:

  “It's not just a rule on Dateline 101, it's also Law Enforcement 101, that the spouse is always suspect until he's not.” (03:58)

• On the emotional toll of the Gacy investigation:

  “One great hope of mine is that maybe through telling the story and just like shedding a different kind of light on it, that maybe we aid in putting a name to one or two or three of those boys that still are unknown their identities.”
  (Brad Davis, 31:14)

• Donna Adelson, denying guilt at sentencing:

  “But I had no knowledge that this horrible, evil act was going to take place. If I had become aware of this plan before Danny was murdered, I would have stopped it.”
  (21:36)

Timestamps for Major Segments

• Sievers Case: 01:40 – 10:25
• Clenney Case: 12:35 – 17:11
• Adelson, Greenberg, Richins Updates: 19:38 – 25:05
• John Wayne Gacy Series Interview: 25:17 – 31:29

Conclusion

This episode of Dateline: True Crime Weekly provides thoughtful updates and expert discussion on high-profile crimes, legal drama, and their broader human impacts. The team goes beyond the headlines, with deep dives into courtroom strategy, emotional interviews, and a commitment to highlighting victims’ stories.

For extended interviews and related documentaries, listeners are directed to stream content and bonus material on Peacock.