LOS ANGELES (AP) — The mother of the man who killed four people at a Manhattan office tower home to the NFL before taking his own life 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 accused the football league of hiding the dangers of brain injuries linked to contact sports.

His mother told the dispatchers on Sept. 12, 2022, that her son was also struggling with depression, chronic migraines and insomnia; was taking sleeping pills and smoked 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 and reported that her son was threatening to hurt himself.

“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.”

She told dispatchers she would wait in the stairwell because she did not want Tamura to know she had called the police.

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.

Tamura, 27, worked at the Horseshoe Las Vegas until last week, when authorities say he drove his car to New York and carried out the shooting.