Shane Tamura killed four people at a Manhattan office building Monday, including Blackstone executive Wesley Lepatner and New York City police officer Didarul Islam. The head of the NYPD said investigators plan to question a man who supplied parts for the gun that was used in the attack.

Standing in the rain, NYPD Officers, NYPD Cadets and other members of law enforcement attend funeral services for slain New York City Police Officer Didarul Islam, in the Bronx borough of New York City,