Police searched Shane Tamura’s employee locker at a Las Vegas Strip casino in their attempts to piece together why he killed four people and then himself in New York City earlier this week, the 8 News Now Investigators have learned.

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.

Authorities say the man who killed four people at a Manhattan office building bought the rifle he used in the attack and the car he drove across country from his supervisor at a Las Vegas casino