UPDATE 9:13 AM PT Authorities now say the shooter had no ties to any international terrorist group.
Police have identified the lone shooter responsible for opening fire Sunday night on the Route 91 Harvest Fest -- killing at least 58 people and injuring more than 500 others.
Cops in Las Vegas say the shooter, 64-year-old Stephen Paddock, was located in a room on the 32nd floor of the Mandalay Bay Resort and Casino. Police had been seeking Paddock's girlfriend, Marilou Danley, as a person of interest, but they've found her and say she was NOT involved in the shooting.
ISIS is now claiming responsibility for the massacre, and claiming Paddock converted to Islam months ago.
Police say Paddock lived in nearby Mesquite, Nevada in a retirement community ... and did not have any previous criminal record there. His age does not fit the typical profile in mass shooting cases. Cops say when they stormed his room they found him dead.
It's clear from the horrific videos from the scene -- the deadliest mass shooting in U.S. history -- that Paddock rained down hundreds of rounds from an automatic weapon before he was killed. He reportedly had nearly 10 more weapons with him in the hotel room.
Jason Aldean was performing when the shooting began. He and his band were able to scramble to safety as bullets reportedly ricocheted onto the stage.
At least one off-duty police officer is among the fatalities.