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.

A vigil will also be held Friday night for NYPD Officer Didarul Islam so the community can come together in mourning. CBS News New York's Christina Fan reports.