The man who police say shot and killed four people Monday, July 28, in New York City was a former high school football player in California, according to multiple reports and information collected by USA TODAY Sports.

Shane Tamura, 27, of Nevada was identified by police as the person who stormed into a Midtown Manhattan office building where the NFL and other prominent businesses are headquartered. NFL Commissioner Roger Goodell said one NFL employee was shot and seriously injured, according to a memo he sent to NFL staff that was obtained by USA TODAY Sports.

More: Gunman kills 4, then himself in NYC shooting rampage

Mayor Eric Adams said on Tuesday, July 29, that preliminary investigations show the gunman may have targeted the NFL offices on floors 5-8 of the 44-floor building but entered the wrong elevator shaft and ended up on the 33rd floor instead, where he then killed himself.

Tamura left behind a three-page note claiming he had chronic traumatic encephalopathy, according to multiple media reports. CTE is a brain condition experienced by people who have repeated blows to the head, often through contact sports such as football.