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.

Crazed gunman Shane Tamura, who shot dead four people at a Midtown Manhattan office building before turning the gun on himself last Monday, suffered from a sports-related concussion and multiple alarming mental health episodes that led his mother to call 911 on him, according to new details released by authorities.