Suvechha Sarkar
On July 18, 2014, the life of law professor Daniel Eric Markel — lovingly known as Dan — came to an abrupt end when he was killed in his garage in Tallahassee, Florida. What followed was a years-long investigation that would reveal a murder-for-hire plot, where the two hitmen were Luis Rivera and Sigfredo Garcia. The case comes into focus on NBC’s ‘Dateline: Deadly Mischief’ and ABC’s ’20/20: First Divorced Then Dead.’ It revealed how Dan’s former brother-in-law and his ex-girlfriend, Katherine Magbanua, were involved in the murder. It additionally features officials who worked tirelessly on the case and his loved ones.
Luis Rivera and Sigfredo Garcia Were Arrested Based on CCTV Footage and Phone Records
Daniel Eric Markel, whose loved ones also called him Dan, was shot in the garage of his home in Tallahassee, Florida, on July 18, 2014. Although paramedics rushed him to the nearest medical center, he sadly passed away from his gunshot wounds on July 19. It led to the launch of a homicide investigation that led detectives to first question Dan’s ex-wife, Wendi Adelson. According to police records, she admitted that her mother, Donna Adelson, and brother, Charles Adelson AKA Charlie, fostered hostile feelings towards Dan because of the custody battles over Wendi’s children and her messy divorce from him. Although she insisted they had nothing to do with the murder, she mentioned that Charles had once jokingly told her that hiring a hitman to kill Dan would be cheaper than paying for the custody battle.
According to official reports, Wendi’s ex-boyfriend, Jeffrey Lacasse, insisted that Charles and Donna might be involved in the murder. In the meantime, investigators reportedly learned from one of Dan’s neighbors that a green Toyota Prius fled the scene around the time of the murder. Upon reviewing the CCTV footage from Dan’s gym, they discovered that the vehicle had followed him home from there. Several other cameras had also captured the car and its distinct SunPass toll transponder. However, since there were no toll booths at that time in Tallahassee, officials expanded the search to the entire state. It wasn’t until 2016 that they traced the Prius to a rental car service in Miami, Florida. Upon checking their register, it was revealed that Luis Rivera and Sigfredo Garcia rented the car.
Police records state that detectives found out that while Sigfredo was involved with low-level criminal activities, Luis was a part of the gang, the Latin Kings. While they reportedly used cell tower pings to place both of them at the scene of the crime, they also discovered that Sigfredo had called Katherine Magbanua after the murder. What shocked them was that Katherine was Charlie’s ex-girlfriend. According to investigative reports, Katherine was on the payroll at Charlie’s father’s dental practice and received several checks from them. Moreover, a few months after the crime, she deposited a substantial amount of cash into her bank account. Ultimately, on May 25, 2016, Sigfredo was arrested and charged with the first-degree murder of Dan and conspiracy to commit first-degree murder. By then, Luis was already in prison for a drug-related charge, and he was indicted on the charge of first-degree murder.
Testimony From a Hitman and an FBI Sting Led Detectives to Katherine Magbanua
Officials were also investigating Katherine and Charlie’s involvement in Dan’s murder. According to court records, FBI agents conducted a sting operation in the Spring of 2016. An undercover agent who posed as Sigfredo’s acquaintance bumped into Donna and demanded money from her. Records state that it prompted her to call Charlie, who then called Katherine regarding the matter. Luis eventually pleaded guilty to the lesser charge of second-degree murder in return for his testimony against the other co-defendants on October 4, 2016. Already serving a 12-year federal sentence for drug-related charges, he received a concurrent 19-year prison term for murder.
Court records state that Luis confessed that Sigfredo asked him to join him for the murder. He reportedly admitted that Sigfredo pulled the trigger. Luis informed the officials that a lady was paying them around $100,000 because she wanted her two sons back in South Florida. In October 2016, Katherine was finally arrested and charged with first-degree murder, conspiracy to commit first-degree murder, and solicitation to commit murder. Although prosecutors reportedly offered her immunity in return for her testimony, she denied it. Katherine reportedly insisted on not having any involvement in Dan’s murder.
While Sigfredo, Katherine, Charlie, and Donna Are Incarcerated at a Florida Prison Facility, Luis is Likely in the State Prison
The joint jury trial of Sigfredo and Katherine began on September 23, 2019. During the trial, the prosecution presented Wendi and Luis as witnesses before the court. Luis reportedly testified that Sigfredo had hired him for the murder, and the communications regarding the plot happened via Katherine, who was also the mother of Sigfredo’s children. The prosecution also produced phone records and call-pattern evidence. On the other hand, Katherine’s defense claimed that she had no involvement in the crime. She took the stand herself and denied having any connection to the case. According to court records, Katherine claimed that Charlie was responsible for the murder. Sigfredo’s defense reportedly questioned the state’s evidence and insisted that he was not guilty of the charges against him.
Ultimately, on October 11, 2019, the jury found Sigfredo guilty on all counts. However, the jury was unable to reach a verdict for Katherine, and the judge declared a mistrial. On October 15, 2019, Sigfredo was sentenced to life in prison without the possibility of parole for murder and an additional 30-year term for conspiracy. By April 21, 2022, Charlie was arrested and charged with first-degree murder, conspiracy to commit murder, and solicitation to commit murder. The second trial of Katherine began in May 2022, during which the prosecution emphasized that she was the connection between the hitmen and the mastermind, Charlie. They also presented a video of her restaurant meeting with Charlie back in April 2016, where he had mentioned going to the airport if officials found any evidence against him.
Katherine’s defense reportedly tried to shift the blame to Charlie. The jury eventually found her guilty of all charges on May 27, 2022. She was sentenced on July 29, 2022, to life imprisonment without parole for murder, plus two consecutive 30-year terms for conspiracy and solicitation. Katherine testified during Charlie’s trial in October 2023, admitting that she lied about her involvement. He was found guilty in November 2023 and was sentenced to life in prison without parole. Donna was arrested in the same month with the exact charges as Charlie and was convicted and sentenced to life imprisonment without parole. While Sigfredo is currently serving his sentence at Liberty Correctional Institution in Bristol, Florida, Katherine is incarcerated at Lowell Correctional Institution Annex in Ocala, Florida. Luis served his time in an Arizona Federal Prison and was likely released on June 30, 2025. He is now seemingly serving his time at a Florida State Prison.
