Four people were killed and a fifth was injured in a mass shooting at a Midtown Manhattan office building on Monday. The injured victim was an employee at the NFL, according to NFL Commissioner Roger Goodell. Here's what we know about the four people killed:

A vigil will also be held Friday night for NYPD Officer Didarul Islam so the community can come together in mourning. CBS News New York's Christina Fan reports.

The four victims who were killed inside a Midtown office building ​on Monday include an NYPD officer, a security guard, a Blackstone employee and a Cornell grad.