Shooter in Orlando massacre was licensed security officer

Terry DeCarlo, executive director of the LGBT Center of Central Florida, left, Kelvin Cobaris, pastor of The Impact Church, center, and Orlando City Commissioner Patty Sheehan console each other after a shooting involving multiple fatalities at a nightclub in Orlando, Fla., Sunday, June 12, 2016. (AP Photo/Phelan M. Ebenhack)
photo Jermaine Towns, left, and Brandon Shuford wait down the street from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. Towns said his brother was in the club at the time. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)

photo Orlando Police officers direct family members away from a multiple shooting at a nightclub in Orlando, Fla., Sunday, June 12, 2016. A gunman opened fire at a nightclub in central Florida, and multiple people have been wounded, police said Sunday. (AP Photo/Phelan M. Ebenhack)

What we know

MASS CASUALTIES: At least 50 people are dead, and 53 were hospitalized, most in critical condition, officials said.