LAS VEGAS, NV - OCTOBER 02:  Police officers stand by as medical personnel tend to a person on Tropicana Ave. near Las Vegas Boulevard after a mass shooting at a country music festival nearby on October 2, 2017 in Las Vegas, Nevada .A gunman has opened fire on a music festival in Las Vegas, leaving over 20 people dead. Police have confirmed that one suspect has been shot. The investigation is ongoing.  (Photo by Ethan Miller/Getty Images)