Police have identified the man who they say entered a Midtown Manhattan office building wearing body armor and opened fire, killing four people with a high-powered rifle, as Shane Devon Tamura.

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

A Nevada man recently traveled to New York City, entered a Manhattan building wearing body armor, carrying an M4 rifle, and fatally shot four people Monday evening, including a New York Police Department officer and injured another,