The Boulder shooting suspect ‘blacked out’ and violently assaulted a classmate in 2017, police report says

• The suspect in Monday's mass shooting in Boulder attacked a classmate in 2017, a police report said.
• The report said Ahmad Alissa punched a classmate multiple times during a high-school math class.
• Alissa told police the classmate bullied him, but witnesses said they didn't know of a falling out.
• Visit Insider's homepage for more stories.

The suspect accused of killing 10 people at a Boulder, Colorado, grocery store on Monday had pleaded guilty to assaulting a high-school classmate four years prior, according to a police report obtained by The Daily Beast.

Ahmad Al Aliwi Alissa, 21, has been arrested in connection to the mass shooting at a King Soopers grocery store in Boulder Monday afternoon.

Following Alissa's arrest, The Daily Beast found that Alissa had pleaded guilty to attacking a classmate in his final year at Arvada High School in November 2017, and was sentenced to two months of probation and 48 hours of community service.

The attack had left the classmate bleeding, crying, and throwing up, according to the police report.

According to the report, at the end of a math class, Alissa started punching classmate Alex Kimrose multiple times in a seemingly unprovoked attack, leaving Kimrose "bleeding from the nose" and mouth, and causing his face to become so "red and swollen" that his right eye was "partially closed."

Witnesses told police that Alissa was quiet during the attack, Kimrose didn't fight back, and that the assault only ended when the teacher broke it up.

When Kimrose's father picked him up from school, the school's resource officer said Kimrose "was still upset and was crying and throwing up," per the report. The father and son insisted on pressing charges against Alissa, who was suspended over the incident.

Alissa said he was bullied

In a written statement and police interview after the 2017 assault, Alissa claimed that Kimrose "had been bullying" him for the past year, and called him racist names like "terrorist," according to the police report. Alissa's family emigrated to the US from Syria in 2002, when Alissa was a toddler, according to CNN.

He wrote in his written statement that he "could not take it anymore" so Alissa "blacked out and rushed" Kimrose, according to the police report. "I don't remember the incident that much," he wrote, per the report.

The school's resource officer noted that there was no history of Alissa complaining about Kimrose bullying him at the school, and that those who witnessed the assault largely said it seemed random and that they didn't know of any bad blood between the two.

Hallie Smith, a classmate who witnessed the attack, told authorities that a few weeks earlier, Kimrose had taken a video of her going up to Alissa and asking for her phone (which her friends had hidden elsewhere), but said it was "really a joke on her, not Ahmad." She said the video was online for a short time.

In his interview with police, Alissa brought up being mad about a video that Kimrose posted online, in which Kimrose called him a nerd.

Alissa told the officer that on the day of the assault "he saw Alex talking with some kids, and Alex was laughing."

"Ahmad said he felt like Alex was laughing at him and that made him mad. I asked if Alex had said anything to him that day, or was specifically looking or pointing at him, and Ahmad told me no. He said that he just always feels that when Alex is laughing that it is because Alex was making fun of him," the officer wrote, according to the report.

A history of violence

The details of the assault mirrored how other former classmates and Alissa's brother described the suspected gunman.

Dayton Marvel, who was on Alissa's high-school wrestling team, told The Denver Post that he was "kind of scary to be around" and once had an outburst during an intra-team match where he threatened to kill people."

"Nobody believed him. We were just all kind of freaked out by it, but nobody did anything about it,"Marvel said.

Marvel added that Alissa was especially sensitive about his faith, saying: "He would talk about him being Muslim and how if anybody tried anything, he would file a hate crime and say they were making it up."

Another teammate, Angel Hernandez, said Alissa appeared to be paranoid.

"He was always talking about [how] people were looking at him and there was no one ever where he was pointing people out," Hernandez said.

"If he did get ticked off about something, within a split second, it was like if something takes over, like a demon. He'd just unleash all his anger."

Brother says Alissa became 'anti-social'

In interviews with CNN and The Daily Beast, Alissa's brother said he had been the target of bullying in school and that it had made him "anti-social."

"The guy used to get bullied a lot in high school. He was like an outgoing kid, but after he went to high school and got bullied a lot, he started becoming anti-social," Alissa told The Daily Beast.

Ali Alissa said he believes his brother did not commit the shooting as a "political statement," but that it was a result of "mental illness."

Ali Alissa told CNN that he had witnessed his brother becoming more paranoid in recent years. He said it started in 2014, when his brother started to believe he was being followed and chased.

"He would say, 'Someone is chasing me, someone is investigating me.' And we're like, 'Come on man. There's nothing' ... He was just closing into himself,"Ali Alissa said.

The Daily Beast also uncovered a second police report connected to Alissa, in which an ex-girlfriend claimed he damaged some of her furniture, but Alissa was never charged with a crime.

Alissa's paranoia was apparent on his Facebook, which has since been taken down, but which the The Denver Post was able to confirm was his. In one of the posts, he expressed the belief that his high school is tapping his phones out of "racism."