Authorities are still trying to understand what drove Stephen Paddock, 64, to hole up in the Mandalay Bay Resort and Casino in Las Vegas and open fire on a crowd of concertgoers Sunday night, killing at least 59 people and injuring more than 520. Paddock โ who killed himself when SWAT teams breached his room โ apparently acted alone, and meticulously planned his massacre. He had at least 23 firearms in his hotel room, including two rifles mounted on tripods in the windows. Criminology professor James Alan Fox emphasized Paddock did not simply “snap,” while President Trump called the shooter “a sick man, a demented man.” The FBI said Paddock has “no connection” to any international terrorist group, after the Islamic State claimed responsibility for the attack.