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.

The shooting occurred in the lobby of 345 Park Avenue on East 52nd Street, an office building that records indicate is home to the NFL, Blackstone and KPMG.

The police officer who was killed when a gunman opened fire in a Manhattan building was a dedicated father who was working a second job as a security guard.