At least three people were killed and three others were injured by a gunman at the Grand Sierra Resort casino in Reno, Nevada, on Monday, authorities said.Reno Police Chief Kathryn Nance and Sparks Police Chief Chris Crawforth were among a number of officials who held an afternoon press conference to provide an update on the shooting,

The gunman shot five people at a valet area, fired at a resort security guard, who wasn’t injured, and then fatally shot someone driving by before police shot him, authorities said.

A day after a gunman armed with multiple rounds of ammunition shot six people, killing three, at the Grand Sierra Resort in Reno, the shooter's identity and any possible motive are still not known.