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

Blackstone employees struggled on Tuesday to come to terms with the death of Wesley LePatner, one of the investment firm's senior executives who was gunned down late on Monday as she was leaving her Midtown Manhattan office.

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.