New York City experienced another tragedy after Shane Tamura opened fire in Manhattan, killing four as well as himself, police say. Tamura, 27, of Las Vegas, felt he was experiencing the impacts of CTE,

Once a promising athlete, the 27-year-old faded from public view—until he showed up at 345 Park Avenue, gun in hand.

The gunman suspected of targeting the National Football League headquarters in New York, killing four, was a former football player at two Southern California high schools.