Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday. One slain victim worked at Rudin Management -- which is located on the 33rd floor of 345 Park Avenue, where the shooter died by suicide -- the company said. The employee's name was not released at the family's request.

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.