Police investigate the back of the Pulse nightclub in Orlando on Sunday, June 12. At least 49 people were killed there by Omar Mateen, who was shot and killed by Orlando police. It was the deadliest mass shooting in U.S. history. Phelan M. Ebenhack/AP

Bodies arrive at the medical examiner's office on June 12. Alan Diaz/AP

Friends and family react after a list of hospitalized victims is released June 12 outside a hotel near the Orlando Regional Medical Center. Loren Elliott/Cal Sport Media/Zuma Press

Pastor Kelvin Cobaris embraces Orlando City Commissioner Patty Sheehan, right, and Terry DeCarlo, executive director of the LGBT Center of Central Florida, on June 12. Phelan M. Ebenhack/AP

Jeremy Glatstein donates blood in Orlando on June 12. He drove an hour to the donation center to show his support for the shooting victims. Courtesy David Waters

A bomb disposal unit checks for explosives around the apartment building where Mateen is believed to have lived in Fort Pierce, Florida. Joe Raedle/Getty Images

Ray Rivera, a DJ at the nightclub, is consoled by a friend outside of the Orlando Police Department. Joe Burbank/Orlando Sentinel/AP

Florida Gov. Rick Scott arrives at the scene. Joe Burbank/AP

Police gather outside the home in Port St. Lucie, Florida, where Mateen's father lives. CNN

Police officers gather outside of the nightclub, which describes itself as "the hottest gay bar" in the heart of Orlando. Gerardo Mora/Getty Images

Ron Hopper of the FBI answers questions from members of the media on June 12. Listening are Orlando Police Chief John Mina, left, and Orange County Mayor Teresa Jacobs. Phelan M. Ebenhack/AP

A police officer stands guard outside the Orlando Regional Medical Center. Phelan M. Ebenhack/AP

A SWAT team member arrives at the scene of the shooting. Phelan M. Ebenhack/AP

Medical personnel wait with stretchers at the Orlando Regional Medical Center. Phelan M. Ebenhack/AP

People wait for news outside the emergency entrance of the hospital. Phelan M. Ebenhack/AP

Police in Orlando direct family members away from the scene of the shooting. Phelan M. Ebenhack/AP

Shooting victims are attended to by emergency responders outside the club. Univision Florida Central/EPA

Emergency personnel gather outside the nightclub. Unision Florida Central/EPA

Bystanders wait at the scene. Phelan M. Ebenhack/AP