People scramble for shelter at the Route 91 Harvest country music festival after a gunman opened fire on the crowd in Las Vegas.

The gunman, identified by police as 64-year-old Stephen Paddock, was found dead in a hotel room at the Mandalay Bay Mandalay Bay Resort and Casino.

People flee the Route 91 Harvest country music festival grounds after a active shooter was reported on October 1, 2017 in Las Vegas, Nevada.

Las Vegas Metro Police and medical workers stage in the intersection of Tropicana Avenue and Las Vegas Boulevard South after a mass shooting at a music festival on the Las Vegas Strip.

People run for cover at the Route 91 Harvest country music festival in Las Vegas after gunfire was heard. 

Police later said a lone gunman opened fire from a window on the 32nd floor of the Mandalay Bay Hotel and Casino.

People attending the Route 91 Harvest music festival crouch down for cover as a gunman opens fire from the 32nd floor of a hotel in Las Vegas, Oct. 1, 2017.

People run from gunfire at the Route 91 Harvest country music festival in Las Vegas.

People take cover at the Route 91 Harvest country music festival in Las Vegas after gunfire was heard on October 1, 2017. 

Police later said a lone gunman opened fire from a window on the 32nd floor of the Mandalay Bay Resort and Casino.

Police and rescue personnel gather at the intersection of Las Vegas Boulevard and Tropicana Ave. after a mass shooting at a country music festival.

Armed police respond to the scene of a shooting near the Mandalay Bay Resort and Casino on the Las Vegas Strip, Oct. 1, 2017.

Police officers stop a man who drove down Tropicana Ave. near Las Vegas Boulevard and Tropicana Ave, which had been closed after a mass shooting at a country music festival. The man was released.

Police later identified the lone gunman as 64-year-old Stephen Paddock, who opened fire from a 32nd floor hotel room and was found dead.

Las Vegas police on the streets outside the the Route 91 Harvest country music festival grounds after a active shooter was reported on October 1, 2017.

A pair of cowboy boots is seen in the street outside the concert venue after the mass shooting on the Las Vegas Strip.

They belonged to concertgoer Stephen Vicelja, who was shot in the leg and said a bystander helped him take off the boots to bandage the wound. 

People provide help after a gunman opened fire on attendees of the Route 91 Harvest country music festival in Las Vegas, Oct. 1, 2017.

A cowboy hat lays in the street after shots were fired near a country music festival on October 1, 2017 in Las Vegas, Nevada.

A woman cries while hiding inside the Sands Corporation plane hangar after a mass shooting at the Route 91 Harvest music festival in Las Vegas on Sunday, Oct. 1, 2017.

A Las Vegas Metropolitan Police officer stands in the intersection of Las Vegas Boulevard and Tropicana Ave. after a mass shooting at a country music festival nearby. 

Scene of the shooting at the Route 91 Harvest music festival, with the Mandalay Bay Resort and Casino behind the stage. 

Police said the gunman, identified as Stephen Paddock, 64, was found dead in a room on the 32nd floor of the Mandalay Bay where he'd been shooting down into the crowd.

Police officers take cover near scene of a shooting near Mandalay Bay Resort and Casino on the Las Vegas Strip on Oct. 1, 2017.

A man in a wheelchair is taken away from the Route 91 Harvest country music festival in Las Vegas after a gunman opened fire on Oct. 1, 2017.

A woman sits on a curb at the scene of the shooting outside of a music festival along the Las Vegas Strip, Oct. 2, 2017.

A person runs from the Route 91 Harvest country music festival in Las Vegas after gunfire was heard on Oct. 1, 2017.

Las Vegas police patrol along the streets outside the the Route 91 Harvest country music festival grounds after a active shooter was reported.

The gunman, identified by police as 64-year-old Stephen Paddock, was later found dead in a hotel room at the Mandalay Bay Mandalay Bay Resort and Casino.

Drapes billow out of broken windows at the Mandalay Bay Resort and Casino in Las Vegas on Monday, Oct. 2, 2017, the morning after the deadly shooting. The gunman, identified as Stephen Paddock, 64, was found dead inside a hotel room on the 32nd floor.

An investigator works in the room at the Mandalay Bay Resort and Casino in Las Vegas where gunman Stephen Paddock opened fire on a music festival, killing dozens and wounding more than 500 people.

Investigators walk through debris on festival grounds across the street from the Mandalay Bay Resort and Casino on Tuesday, Oct. 3, 2017, in Las Vegas. Authorities said Stephen Craig Paddock broke windows in his hotel room and began firing with a cache of weapons, killing dozens and injuring hundreds at the festival.

A candlelight vigil was held in Las Vegas on Monday, Oct. 2, 2017, to honor the victims of the nation's deadliest mass shooting.

Destiny Alvers, who attended the Route 91 country music festival and helped rescue her friend who was shot, visits a makeshift memorial near the Mandalay Bay hotel on the Las Vegas Strip on Oct. 3, 2017.

A couple write a message at a makeshift memorial on the Las Vegas Strip on Oct. 3, 2017.

Hundreds of people lined up to donate blood after the deadly shooting rampage. Here, Sammi Rangel -- wearing a "We love you Las Vegas" t-shirt -- gives blood at a center in Las Vegas on Oct. 3, 2017.