The man suspected of opening fire Saturday on a public bus on the Las Vegas Strip did so for “no apparent reason,” police said Sunday. The suspected shooter, identified as Rolando Cardenas, caused chaos in the crowded tourist hot spot after firing at fellow passengers as they got off the bus and then barricading himself inside. A 57-year-old Montana man identified as Gary Breitling was killed in the shooting, and another passenger was wounded but is expected to recover, the Associated Press reported. Police are still trying to get to the bottom of what happened on the bus just prior to the shooting, when Cardenas allegedly stood up and began firing at passengers at a stop near the Cosmopolitan hotel-casino. Cardenas, who surrendered to police after an hours-long standoff, has been booked on suspicion of murder, attempted murder, burglary, and opening fire on the bus. Assistant Sheriff Tom Roberts said Sunday that investigators believe “mental issues” may have played a role in the shooting.