Naman Shrestha
A popular figure in the entertainment industry, Michael Castagne, was found dead in his office suite in Richardson, Texas, in November 2015. The unexpected tragedy sent shockwaves across the entire community as the detectives launched a homicide investigation. Within hours, they apprehended the unlikely perpetrator, thanks to a witness statement. The entire case and the investigation that ensued are covered in a detailed manner in Investigation Discovery’s ‘Lethally Blonde: Bad Medicine,’ which also features exclusive and in-depth interviews with Michael’s loved ones and the officials who helped solve the case.
Michael Castagne’s Remains Were Still Smoldering When Firefighters Entered His Office
Born around 1955, Michael Castagne worked in the restaurant industry for most of his life, during which he also helped launch a popular Addison wine bar. Having a mysterious personality, he was known to lead a private life, keeping his personal details to himself. Later, he reportedly established an adult website called Nu-Faces, which created the “adult stars of tomorrow.” Michael was also employed at a marketing and web design company in an industrial park at 500 East Arapaho Road in Richardson, Texas. His life was suddenly cut short on November 17, 2015.
On the fateful evening at around 6:07 pm, the Richardson Fire Department was notified about smoke emerging from Michael’s office suite. As the firefighters entered the site to investigate the smoke, they found 60-year-old Michael Castagne lying dead under a plastic cover on the floor of his office. The cause of his death was determined to be blunt force trauma to the head. As the detectives inspected the crime scene, they found no signs of forced entry and noticed that Michael’s red Kia Sportage, video cameras, and a laptop had been stolen. The investigators theorized that the perpetrator intentionally set the fire to destroy the evidence. Without any delay, a homicide investigation was launched.
Michael Castagne’s Killer Had an Altercation With Him That Led to the Murder
As part of the investigation, the detectives interviewed a witness who had arrived at Michael Castagne’s office suite a few hours before the murder took place. He told them he responded to a Craigslist advertisement seeking models and actors. The witness claimed to have heard an argument between Michael and another male individual, whom he identified as Demonte Magnum, by going to Michael’s website. According to him, Demonte was 100 percent the man arguing with Michael on the fateful day. Digging deeper into the case, the investigators searched Michael’s home and found folders labeled with stage names. It included the name of their suspect, Demonte Magnum, whose government name was Daeveion Demonte Mangum.
Daeveion had apparently worked with Michael Castagne for his company, The Brotherhood LLC, billed as a marketing and web design firm. Soon, the detectives tracked down the suspect to his Fort Worth residence, where they also discovered Michael’s stolen SUV. Within a few hours of the investigation, Daeveion was arrested at the apartment on outstanding traffic warrants and held at the Richardson City Jail. As they combed through his house, they also found Michael’s other stolen belongings, including the cameras and laptop, hidden under the bed. The two men had reportedly collaborated on at least three adult films. During the interrogation, Daeveion reportedly cooperated with the detectives and admitted to killing Michael after getting into a heated argument with him. He was then charged with the homicide and held on a $500,000 bond.
Daeveion Mangum is Currently Incarcerated at a Texas Prison
In early August 2016, Daeveion Demonte Mangum stood trial for killing 60-year-old Michael Castagne in his Richardson office. During the trial, the defense tried its best to prevent the defendant from getting a life sentence. They told the jury that Daeveion killed Michael in a fit of “sudden passion.” They also claimed that Michael had been grooming the defendant the same way a sexual predator would groom a child. Daeveion’s mother, Kizzie Sanders, also took the stand and stated, “He was trying to provide (for his family), but he seeked the wrong way. There are people out there who will try to hurt you no matter how old you are.”
Meanwhile, the prosecution dismissed the argument, stating, “This was not a 7-year-old with candy. This is a 20-year-old man with a wife and kids he kept in the dark. They argued that he tried to burn down the office as he knew what he had done. His wife, Dashunna Mangum, requested the jury to be lenient for her and their kids. Daeveion also took the stand and admitted to killing Michael, but testified, “I was thinking that’s what it takes to be a p**n star.” Defending himself, he told the jury that he had acted in self-defense after Michael allegedly threatened to strike him with a hammer.
The killer claimed that he picked up the hammer and struck Michael with it more than 30 times because he thought his life was in danger. Ultimately, the jury convicted him of murder, and on August 5, 2016, he was sentenced to nine years in prison for committing the gruesome crime. As of today, the 30-year-old killer is serving his sentence at the James V. Allred Unit in Wichita Falls, Texas, with his projected release date scheduled for June 2028.
