LOS ANGELES (AP) — The mother of the man who killed four people at a Manhattan office tower home to the NFL told 911 dispatchers during a 2022 incident when he threatened to kill himself that he suffered from a sports-related concussion and other issues, new information released by Las Vegas police Tuesday revealed.

Shane Tamura, 27, had a documented history of mental health problems and carried a handwritten note in his wallet when he carried out the shooting that claimed he had chronic traumatic encephalopathy, known at CTE, investigators said. He fatally shot three people in the building lobby before taking an elevator to the 33rd floor, killing a fourth victim and then ending his own life, according to police.

He accused the football league of hiding the dangers of brain injuries linked to contact sports. Tamura didn’t play professional football but played during his high school years in Southern California, where he grew up.

His mother told the dispatchers on Sept. 12, 2022, that her son was under a doctor’s care for “depression, concussion like sports concussion, chronic migraines, and insomnia.” She also said he was taking sleeping pills, smoking marijuana, and kept a gun in his backpack. It was one of two incidents that led to Tamura being admitted to hospitals for mental health crises.

“He said he’s going to kill himself,” she said in the recorded 911 call. “He didn’t say he made a plan, he just said he just can’t take it anymore.”

Tamura’s mother placed the call from outside a Budget Suites Motel. She told dispatchers she would wait in the stairwell because she did not want Tamura to know she had called the police.

“He just started crying and slamming things and said I’m making him worse, so I said, ‘I’ll step outside,’” she said. “I don’t want you to be upset, but I’m afraid to leave.”

Tamura was committed to a hospital again in 2024 after calling his mother and making statements about wanting to hurt himself, according to a first responder captured on body camera video released by Las Vegas police.

The Las Vegas Metropolitan Police Department said the records, which would normally be withheld due to privacy protections, were being released “in light of the extraordinary circumstances.”

Tamura worked at the Horseshoe Las Vegas’ surveillance department until last week, when authorities say he drove his car to New York and carried out the shooting. He bought the rifle he used in the attack and the car he drove from his supervisor at the casino.

New York City detectives searched Tamura’s locker at the Horseshoe casino Wednesday and found a tripod for his rifle, a box for a revolver that was found in his car in New York, and ammunition for both guns, the police department said.

Police said they also found in his apartment a psychiatric medication, an epilepsy drug and an anti-inflammatory that had been prescribed to Tamura.

His psychiatric history would not have prevented him from legally purchasing the revolver, unless relatives or law enforcement sought a so-called extreme risk protection order from the courts. However, a new state law effective this month will allow officers to confiscate firearms in the immediate vicinity of someone placed on a mental health crisis hold.

Las Vegas police also released records Tuesday related to two other run-ins with the law. Tamura was arrested for trespassing at a casino in 2023, where he became agitated after he was asked to show his ID to collect his winnings and was asked to leave when he refused to. He was also cited for driving an unregistered car and without a license in 2024.