Shane Tamura — who fatally shot four people at a Midtown East office building — said in a suicide note he believed he suffered from CTE and requested his brain be studied.

Police have identified the man who entered a Midtown Manhattan office building wearing body armor and opened fire killing four people with a high-powered rifle.

The gunman, who said in a note he believed he had CTE, targeted skyscraper that houses the NFL's headquarters.