As Tamura waited for a lift after beginning his attack, a woman stepped off, but the gunman spared her and let her pass, Commissioner Tisch said.
He made his way to the 33rd floor, killing one person before walking down a hallway and shooting himself in the chest, she added at a Monday night news conference.
Police searched the suspect’s vehicle, which he had double-parked out at the front, and found multiple magazine rounds and a revolver. The vehicle was registered in Nevada to Tamura, who was a registered gun owner in the state.
US media later reported that a note was found at the shooting scene which appeared to have been written by Tamura. The suspect’s writings are said to have speculated that his mental illness was caused by CTE, a brain disease caused by head trauma that is sometimes seen in sport players.
Tamura was an American football player during his time at high school in California, ex-teammates told NBC News. His note contained vague references to the NFL, according to the police sources who spoke to ABC News.