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.

A gunman opened fire inside a Midtown Manhattan skyscraper on Monday, killing four people, including an off-duty NYPD officer, according to authorities. A video showed

The Bronx community met outside the 47th Precinct to honor the NYPD officer killed in the Midtown mass shooting. CBS News New York's Adi Guajardo reports.