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 ...

After a deadly shooting at an NYC building that housed NFL and Blackstone offices, safety experts say it’s high time ...

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 ...

Most of the damage was relegated to the 33rd flood, where Shane Tamura accidentally rode the elevator while searching for the NFL headquarters.

A Blackstone executive was seemingly a random victim in a mass shooting that left four dead, but some see parallels with the ...

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 ...