The head of the New York Police Department said that investigators plan to question a man who supplied parts for a gun used in the attack on Monday.

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.

Four victims, including an NYPD officer and a Blackstone executive, were killed in an NYC shooting at 345 Park Avenue.

Tamura worked as a surveillance department employee at the Horseshoe hotel and casino in Las Vegas, a spokesperson for the Horseshoe said on Tuesday. Several squad cars from the Las Vegas Metro Police were seen at the entrances to a gated neighborhood where Tamura was believed to have lived.

Tamura had apparently driven across the country from Nevada before killing four people in a shooting rampage in Manhattan.