Blackstone Inc. is reopening its New York headquarters on Monday after keeping the office shuttered in the wake of a shooting spree that killed four people, including one of its senior executives.The firm’s offices at 345 Park Ave.

The victims of the Manhattan office building shooting are identified as NYPD Officer Didarul Islam, Blackstone executive Wesley LePatner, Cornell grad Julia Hyman and security officer Aland Etienne.

Workers in business attire were seen piling couches up against their office door -- with the towering furniture reaching the ceiling.