At least 58 people were killed and hundreds more were injured when a gunman opened fire on a music festival crowd from the 32nd floor of the Mandalay Bay Resort and Casino, Las Vegas, Oct. 1, 2017. The attack is the deadliest mass shooting in modern U.S. history.<br><br>Pictured: People scramble for shelter at the Route 91 Harvest country music festival, Oct. 1, 2017, in Las Vegas.

People tend to the wounded outside the festival grounds.

A wounded person is walked in on a wheelbarrow as Las Vegas police respond during an active shooter situation on the Las Vegas Stirp in Las Vegas Sunday, Oct. 1, 2017. Multiple victims were being transported to hospitals after a shooting late Sunday at a music festival on the Las Vegas Strip.

A wounded woman is moved outside the Tropicana Hotel and Casino during the active shooter situation on the Las Vegas Strip.

People are searched by police at the Tropicana during the active shooter situation.

A man lays on top of a woman as others flee the music festival grounds. The woman was later seen getting up with help.

Police officers advise people to take cover near the scene of the shooting.

People carry an injured person at the music festival grounds after gunfire was heard.

People run for cover at the music festival after gunfire rang out at the festival.

People run from the music festival grounds after gunfire was heard.

People take cover while others flee the music festival grounds.

Police run at the scene of the shooting near the Mandalay Bay Resort and Casino on the Las Vegas Strip.

A man in a wheelchair is taken away from the festival grounds after gunfire ran out.

A woman sits on a curb at the scene of the shooting, Oct. 2, 2017.

People walk near the Las Vegas Strip shortly after sunrise, Oct. 2, 2017.

Drapes billow out of broken windows at the Mandalay Bay Resort and Casino, Oct. 2, 2017.

Two festivalgoers leave the area around the Mandalay Resort and Casino, Oct.2 2017.

Investigators load a body from the scene of the mass shooting, Oct. 2, 2017.

Investigators walk through debris on festival grounds across the street from the Mandalay Bay Resort and Casino, Oct. 3, 2017, in Las Vegas.

Veronica Hartfield (2L) widow of Las Vegas Metropolitan Police Department Officer Charleston Hartfield, their son Ayzayah Hartfield, (2R), their daughter Savannah Hartfield, right, and Hartfield's sister Denita Hartfield ,left, attend a vigil for Charleston Hartfield at Police Memorial Park, Oct. 5, 2017 in Las Vegas.