Shane Tamura said he had CTE. His claim, which is unproven, has again put a spotlight on the NFL's troubling history with its players and the disease.

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

Follow along for live updates with the New York City shooting, where police investigate motive after five people, including ...

The gunman who killed four people at an office building in New York City on Monday evening left his home in Las Vegas, Nevada late last week.