Antoinette Cannon, who worked as a trauma nurse and treated victims of the Las Vegas mass shooting, leaves a rose at each of the 58 white crosses at a makeshift memorial on the south end of the Las Vegas Strip, October 6, 2017 in Las Vegas, Nevada. On October 1, Stephen Paddock opened fire on the crowd at the Route 91 Harvest country music festival, killing 58 people and injuring more than 450. The massacre is one of the deadliest mass shooting events in U.S. history. | Drew Angerer/Getty Images

Pathologists to Search Stephen Paddock’s Brain for Clues to Mass Shooting

Neuropathology experts warn that finding proof of dementia or trauma in the mass shooter's brain isn't likely to provide a definitive reason for his behavior.