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.

Everytown for Gun Safety’s Nick Suplina joins ABC News’ Linsey Davis to unpack what the Manhattan shooting tells us about the effectiveness of some of the strictest gun laws in the U.S.