Multiple casualties as gunman opened fire in the lobby of the midtown Manhattan building on Park Avenue that is home to the Blackstone investment firm and other corporations before moving to other floors.

Two teams NYPD detectives headed to Las Vegas Tuesday, to execute search warrants at Shane Tamura's home and at a gun store where he legally purchased a revolver on June 12 using a Nevada concealed carry permit,

Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday.

The gunman had a ‘documented mental health history,’ but the motive is still unknown, police Commissioner Jessica Tisch said at a news conference.

Four people were killed, including an off-duty New York City police officer, when a gunman opened fire in an office tower before fatally shooting himself, officials said.

A New York police officer, a “beloved” security guard, a young Cornell graduate and a senior executive with investment firm Blackstone were killed Monday when a lone gunman stormed a sprawling office tower in Midtown Manhattan and opened fire.

In light of the shooting in New York City on Monday in which a man killed four people, some safety and workplace experts are saying it’s time to consider legislation aimed at protecting office workers. And many are pointing to a recently enacted law in California as an example of what other states might consider.

Wearing body armor and wielding an assault-style rifle, the alleged gunman burst into a Midtown Manhattan office building shooting victims at random.