The New York City gunman was identified as a 27-year-old who had roots in Southern California and played high school football in Granada Hills.

The 27-year-old man who shot and killed four people at a Midtown office building on Monday carried a note in his pocket claiming he suffered from CTE, asked that his brain be studied and made references to the NFL.

Tamura was involuntarily held after being considered a danger to himself or others, according to a law-enforcement official.