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.

Officer Didarul Islam, 36, who was guarding the building on a paid security job when he was killed, had served as a police ...

What we know about Tamura’s life, how he got the assault rifle that he used to kill an NYPD officer and three others, and the ...

It's a point borne out by recent research from ASIS International, a global organization of security professionals, that showed 14% of companies had no comprehensive plan to address active-assailant ...

A man stalked through a Manhattan office tower firing a rifle, killing four people, including a New York City police officer, ...

Authorities confiscated several items from a Las Vegas apartment tied to a gunman who used an AR-15-style rifle to kill four ...

A security expert offers a list of ‘must-haves’ for workplace safety that may save lives in the event of a mass shooting.

There were 23 shell casings and 13 bullet fragments recovered from the lobby of 345 Park Avenue and 24 spent shell casings on ...

Roger Goodell also gave a health update on the league employee who was seriously injured in the gun attack that killed four ...

Family and friends of the four victims killed in the Midtown mass shooting have spent several days mourning and laying their ...

An off-duty New York City police officer and an executive at an investment firm were among four people killed by a gunman at a Manhattan office tower ...