LAS VEGAS -- The gunman who killed four people before taking his own life in a midtown Manhattan office building that houses the NFL's headquarters had for years sought medical help for frequent, ...

(CNN) — During evening rush hour in New York City on Monday, a man calmly walked into a Park Avenue office building lobby and killed a police officer, then opened fire on other innocent strangers.

Tragedy at 345 Park Avenue last week with the murder of Wesley LePatner, CEO of BREIT, Rudin's Julia Hyman, Aland Etienne and ...