They were taking the final sips of their drinks, closing tabs at the bar and arranging rides home.

Hundreds of young people had packed into Orlando’s Pulse Nightclub for Latino night, a raucous, sweaty dance party featuring bachata, merengue and salsa music. Close to 2 a.m., the booming party at one of central Florida’s most popular gay nightclubs was winding down.

A shooting victim is carried out of the Pulse nightclub Sunday morning in Orlando, Fla. Hundreds of young people had packed into the club for a dance party that was winding down when the shooting started.

“All of a sudden something sounded like firecrackers going off,” Ray Rivera, the club’s DJ, told the Orlando Sentinel. “I lowered the music, it stopped for a second, then all of a sudden it sounded again. Then I turned the music off and basically everyone was just running out.”

In their midst, a gunman was unloading an assault rifle, mowing down panicked club-goers streaming toward exists, seeking cover or crouching on the ground in fear. Witnesses described dead bodies littering the ground and people tampling over each other in their struggle to stay alive.

“It was just complete chaos,” Rivera added.

Because he was close to an exit to escape, the DJ was one of the lucky ones. Police say 50 others never made it out of the venue’s three glitzy rooms, their lives lost in a hail of gunfire that left more than 50 others wounded in what appears to be the deadliest mass shooting in U.S. history.

A few minutes later, Pulse Orlando posted a haunting message on Facebook: “Everyone get out of pulse and keep running”.

The violence couldn’t have come at a worse time. On a “high capacity night” like Saturday, Benjamin Di’Costa, 25, a former Pulse dancer, told the Miami Herald that as many as 800 people might be packed inside the club.

“This is one of the No. 1 destinations for LGBT people to attend in the summertime,” he told the paper. “Mostly people from Central Florida, some people come from Tampa to Orlando.”

While police have not publicly identified the gunman, law enforcement officials and relatives on Sunday identified him as Omar Mateen, a 29-year-old from Fort Pierce, Fla.

“It’s appears he was organized and well-prepared,” Orlando Police Chief John Mina and other officials said Sunday morning said, adding that the shooter had an assault-type weapon, a handgun and “some type of (other) device on him.”

Once he made his way inside the club, Mateen would have had little trouble exacting harm on a large number of people, said Alex Choy, a former club employee. Choy told the Herald that the club has two main rooms, one for performances and drag shows to the left of the front door and a larger dance room to the right that links to an outdoor patio behind the venue.

“It’s a very, very small space,” he said. “Either room you go into. If you go to your left, there’s a small room with the stage. That’s what worries me, if there was any type of shooting, it wouldn’t take much to get everyone. Very close range.”

Jon Alamo told the Associated Press he was at the back of the club’s rooms when saw a man holding a weapon appear in the front of the room.

“I heard 20, 40, 50 shots,” Alamo said. “The music stopped.”

Christopher Hansen, a club-goer who was inside when the shooting began, told AP that he escaped through the back of the venue by crawling on his elbows and knees.

“When I got across the street there was blood everywhere,” he said. “I was helping somebody because he was laying down and I wasn’t sure if he was dead or alive. I took my bandana off, I shoved it in this hole, the bullet hole that was in his back.

“After everybody was out, the shooting was still going and the cops were still yelling, ‘Go! Go! Clear the area, clear the area!'” he added.

Those who survived – like Hansen, who told the AP that he was in the VIP lounge when the shooting began – said they were lucky to be alive.

“I was thinking, ‘Are you kidding me?'” he said. “So I just dropped down. I just said, ‘Please, please, please, I want to make it out.’ And when I did, I saw people shot. I saw blood. You hope and pray you don’t get shot.”

An officer working at the club exchanged fire with the gunman, authorities said. It was then, according to police, that the incident developed into “a hostage situation.” Authorities said the man was armed with a “suspicious device,” in addition to his guns, Mina, the police chief, told reporters.

Within minutes of the shooting, police vehicles and a SWAT team descended on the club.

“I was there,” Ricardo J. Negron posted on the club’s Facebook page several hours later. “Shooter opened fire around 2:00am. People on the dance floor and bar got down on the floor and some of us who were near the bar and back exit managed to go out through the outdoor area and just ran. I am safely home and hoping everyone gets home safely as well.”

After news of the violence spread, friends and family members began the desperate search for news of their loved ones. Standing outside the dance club early Sunday morning, Mina Justice told the Associated Press that she was trying to contact her son, Eddie, and fearing the worst.

He had texted her earlier, she said, telling her that he ran into a bathroom with others to hide from the gunman.

“He’s coming,” her son’s text said.

“The next text said: ‘He has us, and he’s in here with us,'” Justice told the AP. “That was the last conversation.”

Hours later, as investigators surveyed the damage, Chief Mina told reporters Sunday morning that even veteran police officers and members of the SWAT team struggled to wrap their minds around the level of carnage inside the club.

“Just to look into the eyes of our officers told the whole story,” he said. “You could tell that they were all shaken by this incident, by what they saw inside the club. They did an unbelievable job in rescuing as many as 30 hostages.”

“This kind of tragedy takes a toll on everyone, even law enforcement officers,” he added.

For members of central Florida’s gay community, the club was more than a place to dance, it was also a place to convene with family.

“Pulse is like a family,” Di’Costa told the Herald. “Everybody who works there is treated equally. Treated like brothers and sisters. When somebody is hurting or in need, we always look out for each other.”