Defense attorneys haven’t disputed the facts of the decisions made by Kevin Bui, who is accused of setting a fire in Green Valley Ranch that killed five members of a family in August 2020. But they argued to a judge Tuesday that the now 17-year-old didn’t intend to harm anyone, and his life shouldn’t be forever marred by adult murder charges.

In a bid to have his case moved to juvenile court, defense attorneys seek to show Kevin Bui as a bright, empathetic child filled with regret about an impulsive decision that had deadly consequences.

“It really doesn’t make any sense,” said his cousin Timmathy Bui, 19, while on the stand. Timmathy said the two had a close relationship growing up, and he never saw his cousin lash out at anyone when he was angry. “He’s very caring as well. So for this to happen, it just doesn’t add up with all the memories that I’ve had.”

The court also heard from Kevin Bui’s mother and paternal grandmother Tuesday. They talked about him as a respectful, compassionate kid who socialized at the extended family’s gatherings and visited his grandparents often to help around their house.

“Before he was arrested, I would never think that my son would do something like that. He is a good son who listens to his parents,” Kevin Bui’s mother, Nga Nguyen, said through an interpreter.

The five victims killed in the Aug. 5, 2020, house fire on North Truckee Street were Djibril Diol, his wife Adja, their toddler daughter Khadija, Diol’s sister Hassan and her infant daughter Hawa Beye. Three others living in the house, unrelated to the family, escaped.

The family was Senegalese, and until the arrests, fear lingered in the local West African community about whether the victims were targeted because of their race or religion, prosecutors have said.

Police arrested Kevin Bui in January 2021, along with Gavin Seymour, also 17, and a third teenager who was 15 at the time of the arson and whose name has not been released publicly. The Denver district attorney’s office charged Kevin Bui and Seymour as adults. Together, the three face dozens of charges, including first-degree murder after deliberation, attempted murder and murder with extreme indifference.

The court held a transfer hearing for Seymour last week. Judge Martin Egelhoff said he would wait to rule on both transfer requests until after Kevin Bui’s hearing concludes.

Testimony revealed during a preliminary hearing in November that the teenagers had targeted the house a few weeks after Kevin Bui had been robbed of his phone and shoes in the summer of 2020 while trying to buy a gun in Denver. Kevin Bui used the Find My iPhone locator to trace his phone to a spot he believed was 5312 N. Truckee St.

He wanted to go to the house perhaps to find his phone, and possibly vandalize the home, Kevin Bui told an investigator in an interview the morning of his arrest. Video footage the night of the fire showed three people on the property wearing hoods and full face masks.

Testimony during the preliminary hearing revealed the teenagers had brought gasoline to use as an accelerant when setting the fire.

But no one in the house had anything to do with the robbery involving Kevin Bui.

Kevin Bui’s defense attorneys spent Tuesday morning questioning experts who testified about social and psychological development in children. Jacqueline Phillips, an attorney and Thornton City Council member who spent 25 years as a classroom teacher, said based on her review of Kevin Bui’s education records, he showed advanced intelligence in school from an early age and excelled in programs for gifted students. She discussed a common expectation for children with precocious intelligence to display a similar level of maturity in their social skills. But in reality, their social maturity doesn’t develop as quickly as their intellect, she said.

As an example, Phillips pointed to an instance when Kevin Bui wore a T-shirt printed with the name of a pornography website to school. People might expect a teenager as smart as him to know better, but it’s typical for them to have a mismatch between their intellectual development and their social maturity, she said.

Intellectually gifted children will still behave in ways that are “risky; they’re impulsive,” she said. “All your typical middle-school behavior doesn’t change because you’re good at calculus.”

Kevin Bui has shown remorse and confusion about his fateful choice to go to the house on North Truckee Street on that early August night in 2020, said Richard Spiegle, a clinical and forensic psychologist. He gave testimony about the development of the parts of children’s brains that affect decision making and their tendency to act on emotion rather than logic.

Kevin Bui has asked Spiegle to help him understand how he could do what he did, Spiegle testified.

“It appeared to be sincere concern about, ‘Who am I? Why would I do that?’ And he wanted to know, and he was hoping that I could give him some insight into that,” he said.

He said during Kevin Bui’s time in detention, the teen has sought ways to keep his mind busy as a coping mechanism, but has shown empathy for the pain his actions caused and has blamed only himself.

Spiegle described Kevin Bui as overcome with guilt and self-loathing when he does dwell on what happened.

“He doesn’t want to focus on hopelessness. He is aware that thoughts of him being … an evil person will enter his mind. And he wards them off by saying to himself, ‘I’m not a horrible person, I’m not an evil person. What I did was horrible,’” Spiegle said.

Kevin Bui’s defense attorneys said they expect to finish calling witnesses by Wednesday afternoon, and prosecutors will call their own witnesses afterward. The court has allotted three days for the transfer hearing, to continue Monday if needed.