Exclusive video shows SWAT teams executing a search warrant at the Las Vegas apartment of Shane Tamura, the man behind Monday's deadly shooting in New York City that left four people dead.

A Las Vegas man with a mental health condition drove cross-country to Manhattan, where he fatally shot four people in a Park Avenue office building Monday before taking his own life, authorities said.

Police executed a search warrant at the Las Vegas apartment of Shane Tamura, where the items obtained included a goodbye note and a bipod for a rifle.