Over 50 dead, 200 injured in Las Vegas after deadliest shooting in modern US history

PHOTO: A man lays on top of a woman as others flee the Route 91 Harvest country music festival grounds after an active shooter was reported on Oct. 1, 2017 in Las Vegas. The woman later was seen getting up with help.
(David Becker/Getty Images)

More than 50 people were killed and 200 injured when a lone gunman opened fire from a perch high up in the Mandalay Bay Resort and Casino in Las Vegas Sunday night, police said, making it the deadliest shooting in modern U.S. history.

The "nonstop gunfire," according to one witness, sent bystanders outside the resort on the Vegas strip ducking for cover and scrambling for their lives. Tourists hid in their hotel rooms and flights headed into the McCarran International Airport were held elsewhere.

Bystanders sprang into action, caring for the wounded and at least one described someone dying in their arms.

Police said a Las Vegas police officer who was off-duty attending the concert is among the dead.

One video showed the terrifying aftermath as the injured lay on stretchers or on the ground with responders and bystanders surrounding them to give aid. Bystanders made makeshift stretchers out of police barricades, plugged wounds with their hands and used their clothing to try to stanch the bleeding from the wounded.

Videos filmed by onlookers gave a window into the chaos that ensued, with some thinking that fireworks were going off. The final night of the Route 91 Harvest Music Festival was taking place across the street from Mandalay Bay. Jason Aldean was the night's headliner; other performers included country stars Jake Owen, Big & Rich, Luke Combs and Dylan Scott.

In the wake of the shooting, the Las Vegas Police Department said the suspected gunman, who was believed to be a local resident, was on 32nd floor of Mandalay Bay hotel. Police responded to the scene, engaged him and he is now dead. Law enforcement officials identified the suspect as 64-year-old Stephen Paddock.

Authorities were looking for a companion of the shooter, Marilou Danley, and authorities later said this morning, "We're confident -- but not 100 percent sure -- we have located the female person of interest."

"We were just at the concert there, and Jason Aldean was playing," one of the concertgoers, named Mike Cronk, 48, a retired teacher, told ABC News. "Kind of sounded like some fireworks going off. I think there was the first kind of volley, and then all of the sudden second volley. My buddy's like, 'I just got hit, you know.' He got hit three times. Then people started diving for the ground. And it just continued.

"It was pretty much chaotic," Cronk continued. "Lots of people got hit. ... It took a while to get him out. We had to get him over the fence and hiding under the stage for a while, you know, to be safe. And, finally, we had to move him because he had three chest wounds."