Sometimes, the only “why” is because evil exists.

LAS VEGAS — More than 10 months after the deadliest mass shooting in modern U.S. history, police say they are closing their investigation without answering the key question: What drove a gunman to unleash a hail of gunfire that killed 58 people and wounded hundreds more?

But authorities say after hundreds of interviews and thousands of hours of investigative work, they are confident there is no evidence of a conspiracy or a second gunman.

Stephen Paddock was an “unremarkable man” who showed signs of a troubled mind leading up to the Oct. 1 shooting on the Las Vegas Strip, Clark County Sheriff Joe Lombardo said Friday. He also was a reclusive, high-stakes gambler who spent more than $1 million in the year leading up to the shooting.

“What we have been able to answer are the questions of who, what, when, where and how,” Lombardo said. “What we have not been able to definitively answer is … why Stephen Paddock committed this act.”