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

The 27-year-old Nevada man opened fire at a New York City office building, killing at least four people and then himself.

The video above aired in a previous newscast. NEW YORK (PIX11) — A gunman who killed four people in a New York City office before taking his own life had over 800 rounds of live ammunition in his ...