Orlando nightclub shooting: Report reveals new details moments after attack

June 12, 2016: Law enforcement officials work at the Pulse nightclub in Orlando, Fla., following a mass shooting. (AP/File)

ORLANDO, Fla. – The sight of so many injured people lying on the dance floor after the Pulse nightclub attack in Orlando led one officer to ask patrons, "If you're alive, raise your hand," according to a new report from police.

The report reveals nearly half of the 49 victims in the mass shooting last June died on the dance floor without a chance to react or run for help. Another 13 died in bathrooms while waiting for help during a three-hour hostage standoff.

The revelations are part of a 78-page presentation Orlando Police Chief John Mina has given to about 10 police groups to discuss his department's response to the attack, considered the deadliest mass shooting in modern U.S. history.

The Orlando Sentinel obtained a copy of the presentation, which includes diagrams and still photos from body cam footage that shows officers in their initial confrontation with gunman Omar Mateen as they responded to the club at 2:02 a.m. June 12.

The images include Officer Adam Gruler, who was working an off-duty job at Pulse that morning, firing shots at Mateen in the club's doorway. Gruler called a signal 43, which means an officer needs help. When help arrived minutes later, Gruler told them, "He's in the patio!" and shot multiple rounds toward Mateen.

Surveillance video from inside the clubs captures Mateen running from the main dance floor toward the bathrooms.

Nine people died in the north bathroom, where Mateen, 29, was barricaded for much of the standoff, according to the report. Four died in the south bathroom. Eleven died at the hospital or in triage areas set up outside the club.

At 5:02 a.m., some three hours after arriving, police used explosives to breach the building. That's when Mateen was killed in a shootout with police.

Mina's presentation notes that officers rescued people throughout the night. He said he doesn't know if any victims were struck by police gunfire.

The Orlando Police Department was one of 27 agencies responding to the shooting, which also wounded 68 people.

The presentation includes self-assessments and ways the agency might approach such situations differently in the future. It notes better coordination with local fire departments could lead to better communication. Mina said the Orlando Fire Department and Orange County Fire Rescue were not in his agency's command post outside the club.

"Would that have saved any more lives? No. The people who needed care, got care," Mina said. "But the communication would have been better between our two agencies if someone from the fire department would have been in our command post."

The presentation says that fire department officials said the "indirect communication" with law enforcement prevented crews from being informed of the wall breach. For example, many firefighters didn't know police would use explosives to breach the nightclub.