Gavin Seymour (Denver District Attorney’s Office)
A 19-year-old man was sentenced to 40 years in prison Friday for starting a house fire that killed five members of a Senegalese family in Denver’s Green Valley Ranch neighborhood more than three years ago.
Denver District Court Judge Karen Brody sentenced Gavin Seymour to the maximum possible sentence he faced.
“This is a tragedy that is, I’m sure for everyone involved, incomprehensible,” Brody said. “There was a loss of the most innocent of lives.”
A sentencing range of between 16 and 40 years was agreed on when Seymour pleaded guilty in January to a single count of second-degree murder in the Aug. 5, 2020, fire that killed two children and three adults in a home on Truckee Street.
Djibril Diol, 29, his wife Adja Diol, 23, and their daughter Khadija Diol, 1, died in the blaze, along with Djibril’s sister, Hassan Diol, 25, and her 6-month-old daughter Hawa Baye.
Seymour and two other teenagers — Kevin Bui and Dillon Siebert — were accused of intentionally setting the family’s house on fire in the middle of the night. Investigators believe Bui mistakenly thought someone who had stolen his phone lived in the home and set the house on fire as revenge.
Seymour apologized for his actions in court Friday.
“If I could go back and prevent all this I would,” he said. “There is not a moment that goes by that I don’t feel extreme guilt and remorse for my actions. …I want to say how truly sorry I am to the family members and community for all the harm I’ve done.”
The victims’ relatives and friends called for the maximum sentence in court Friday.
“Even if you kill five sheep or goats, you should get a maximum sentence,” said relative Hanady Diol, speaking through a translator over the phone from Senegal. “This person here, they are talking about 40 or 30 years. That just means there is no justice there. There is no judging that the people who died are human beings.”
Seymour, Bui and Siebert planned the fire for weeks, Denver police Detective Neil Baker said in court Friday. The morning after the blaze, Seymour read news articles about the killings, searched online for information about law enforcement agencies and about the prison sentence for murder.
It took investigators months to identify the teens, and Seymour never came forward on his own, Baker said.
“This is by far the worst, most senseless murder investigation I have ever investigated,” Baker said. “…I can’t think of any other one that is more deserving of a maximum sentence allowed… There are five victims. Two were babies.”
Officials investigate a house fire at 5312 Truckee Street in Denver after five people were killed inside on Aug. 5, 2020.
Seymour and Bui were 16 at the time, Siebert was 14. Siebert pleaded guilty to second-degree murder in 2022. The case against Bui is still pending.
“You just don’t know. The family we lost. The community leaders we lost. The brother I lost. The sister I lost,” Ousman Ba said in court Friday. He scoffed. “Asking for 16 years. We’re not going to get five people back. They still had another 40 years to live.”
Several of Seymour’s supporters also spoke in court Friday, describing him as a respectful and gentle teenager who struggled with a learning disability and low-self esteem. That low self-esteem left him vulnerable to peer pressure, particularly during the social disruption wrought by the COVID-19 pandemic, they said.
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Seymour’s attorney, Jenifer Stinson, blamed Bui as the ringleader who drove the trio’s plan to set the house fire, called Seymour a “follower,” and asked the judge to impose the lowest possible prison sentence of 16 years.
“Two things can be true,” she said in court Friday. “You can be a kid who makes a reckless, poorly considered, destructive choice that results in the loss of life… But that same person can be sweet and kind and funny and loving and struggling and hurting. And all of those people are Gavin Seymour.”
Prosecutor Courtney Johnston asked for the maximum 40 years in prison, and noted that Seymour would be eligible for a special early release program in 20 years because he committed the crimes as a juvenile. He could apply for the three-year program in 2041 — 20 years after his arrest — and could be released after completing that program, she said.
Bui, who faces multiple counts of first-degree murder, is next due in court on March 21.
The cases against Bui and Seymour stalled for several months after the pair challenged the legality of the search warrant Denver police used to identify them as suspects in the fire. The Colorado Supreme Court upheld the search warrant in October.
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