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

NEW YORK (Reuters) -Bankers and traders returned to work on a somber Tuesday morning in Midtown Manhattan, New York's financial epicenter, one day after a shooting that killed four people, including a senior Blackstone executive.

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.