Suvechha Sarkar
In July 2014, the residents of Tallahassee, Florida, were shaken to their core by the murder of Daniel Eric Markel, a law professor lovingly known as Dan. The investigation unraveled a divorce dispute between him and his ex-wife, Wendi Adelson, and a murder-for-hire plot by her brother, Charles Adelson AKA Charlie and mother, Donna Adelson. ABC’s ’20/20: First Divorced Then Dead’ and NBC’s ‘Dateline: Deadly Mischief’ revisit the case, exploring how the investigation lasted for years before justice was served. It also features emotional interviews with his loved ones and the officials who worked on the case.
Donna Adelson Grew Hostile Towards Dan After His Divorce From Wendi
Donna Sue Adelson was born on January 5, 1950. As she stepped into adulthood, she crossed paths with Dr. Harvey Adelson. It wasn’t long before they tied the knot in the presence of their family and friends. Harvey was a dentist who founded the Adelson Institute for Aesthetics and Implant Dentistry, located in Tamarac, Florida, where Donna worked as the Office Manager. Over the next few years, she and Harvey welcomed their three children, Robert, Charles AKA Charlie, and Wendi, into the world. However, reports state that Robert later became estranged from the family. On the contrary, Charlie and Wendi were close to Donna.
After Wendi married Daniel Eric Markel AKA Dan, she settled in Tallahassee, Florida. However, Donna, Charlie, and Wendi were unhappy because they wanted Wendi to move to South Florida to be closer to the Adelson family. It raised major problems between Wendi and Dan. As a result, despite having two sons, they separated in September 2012, and the divorce was finalized in July 2013. Since they shared the joint custody of their children, the judge barred Wendi from moving to Miami. According to official records, during the divorce battle, Donna had sent long emails to Wendi, in which she stated that she wanted Dan to suffer. In those emails, she reportedly mentioned that Wendi had the support of her family. Things took a turn when Dan was shot in the garage of his home on July 18, 2014, and passed away the following day.
During questioning, Wendi informed the police that although Donna and Charlie hated Dan, they would never hire someone to kill him. However, reports state that she recalled that Charlie had once joked about hiring a person to kill Dan. In her statements, Wendi claimed that her ex-boyfriend, Jeffrey Lacasse, AKA Jeff, who admittedly didn’t like Dan, could’ve committed the murder. However, he was ruled out as a suspect since he was out of town on July 18, 2014. Shockingly, Jeff told the detectives that Charlie and Donna could be involved. They then focused on a green Toyota Prius that a neighbor had reportedly spotted backing away from Dan’s home after the murder. CCTV footage captured the car following Dan near his neighborhood. Officials discovered that the vehicle had a SunPass toll transponder, leading to a statewide search.
An FBI Sting Operation and Phone Calls Led to the Arrest of Donna Adelson
In 2016, the car was finally traced back to a rental agency in Miami, where the register revealed that gang members, Luis Rivera and Sigfredo Garcia, had rented it. According to court records, investigators could place them at the crime scene during the time of the murder through their cellphone records. Additionally, they discovered that Sigfredo had called a woman named Katherine Magbanua after the murder, who had called Charlie. Further investigation uncovered that she was Charlie’s ex-girlfriend and had made large cash deposits in her bank within just a few months of Dan’s murder. Reports state that she also received checks from Harvey’s dental practice, where Charlie was employed. As per official reports, to better understand the Adelson family’s involvement, an undercover FBI agent approached Donna.
The agent reportedly claimed that he needed $5,000 and was an acquaintance of Sigfredo. Court records state that shortly after, Donna called Charlie, and they agreed to discuss the matter further. He then contacted Katherine and reportedly asked her to find out who it was. Ultimately, Sigfredo was arrested and charged with conspiracy to commit murder and first-degree murder of Dan on May 25, 2016. In the following month, Luis, who was already in prison for an unrelated crime, was charged with first-degree murder. Luis pleaded guilty to second-degree murder on October 4, 2016, and confessed that a “lady” gave him and Sigfredo the order to commit the crime. In the same month, Katherine was arrested and charged with first-degree murder and two other related charges.
During the joint jury trial of Katherine and Sigfredo in September 2019, Sigfredo was found guilty of all charges, while a mistrial was declared for Katherine. Sigfredo was sentenced to life in prison without parole for murder and 30 years for conspiracy on October 15, 2019. In May 2022, the jury found Katherine guilty of all charges during the retrial, and she was sentenced to life imprisonment without the possibility of parole on July 29, 2022. Charlie was arrested and charged with conspiracy and solicitation to commit first-degree murder and first-degree murder in April 2022. On November 6, 2023, he was found guilty of all charges and later sentenced to life in prison without parole. A few days after Charlie’s conviction, Donna was arrested at the Miami International Airport and was indicted on the exact same charges as her son.
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Donna Adelson is Incarcerated at a Florida Prison Facility Today
The jury trial of Donna began on August 22, 2025. According to court records, during the trial, the prosecution pointed out that she was arrested while trying to board a one-way flight to Vietnam, a country without a US extradition treaty. The probable cause affidavit stated that during a recorded jail call between her and Charlie, she allegedly spoke about looking into countries without the extradition treaty. The prosecution claimed that Donna’s plans to relocate Wendi’s children and her growing hostility towards Dan were allegedly the motive for the murder. They also presented witness testimonies before the court.
On the other hand, the defense argued that there was a lack of direct evidence and questioned the credibility of the witnesses. Ultimately, the jury found Donna guilty on all counts on September 4, 2025. Shortly after the verdict, the defendant filed an appeal for a new trial, alleging misconduct and judicial error. However, it was denied in an order in late September 2025. Donna was sentenced on October 13, 2025, to life in prison without the possibility of parole for the murder, plus an additional 30 years on the conspiracy and solicitation counts to run consecutively. Currently, Donna is serving her sentence at the Florida Women’s Reception Center in Ocala, Florida.
