ORLANDO — They held hands and draped arms around each other's shoulders as they approached the imposing brick building.
Their sons and daughters, brothers and sisters, best friends and dancing partners were among the few dozen still missing after the terrorist attack on Pulse, a gay nightclub where a rifle-wielding man had turned a raucous night out into a massacre Sunday.
Thirty-six hours they had waited with no word, while investigators brought body after body out of the club. Forty-nine dead, plus the shooter. Surgeons worked non-stop tending to the wounded.
Cesar Flores walked up to the Beardall Senior Center, where authorities were notifying the families of those killed, to learn the fate of his 26-year-old daughter, Mercedez.
"She is a happy girl all of the time," he told reporters as he left. "She's a hard worker."
The father paused, then corrected himself. She was.
"I'm sorry," he said. "She's gone."
Bullets at closing time
As family and friends learned the fate of loved ones, authorities provided the fullest picture yet of the worst shooting massacre ever on American soil.
The gunman opened fire about 2 a.m. Sunday, just as the night was winding down at Pulse.
Armed with an AR-15 style semiautomatic rifle, a handgun and ammunition, Omar Mateen began shooting continuously and indiscriminately, witnesses said.
An off-duty police officer, working security at the club, responded to the initial shots and exchanged fire with Mateen, according to Orlando Police Chief John Mina. More officers joined the gunfight.
After spraying the club with bullets, Mateen, 29, holed up inside with hostages. More officers hurried to the scene as back-up, Mina said, and Mateen retreated to a bathroom inside.
People who minutes before had been dancing, sipping mixed drinks, laughing under neon lights, pushed into each other in a rush to the exits. Some hid in crawlspaces, under DJ booths, in dark pockets of the club they hoped were safe.
Eddie Justice texted his mom from a bathroom.
"Mommy I love you. In club they shooting," he wrote, according to texts Mina Justice showed to reporters.
"Trapp in bathroom," he said.
"I'm gonna die."
Tactical teams assemble
Mateen had taken between four and five hostages in one bathroom, according to police, while another 15 or 20 club-goers huddled in another.
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Tactical teams began assembling outside.
At some point while Mateen was in the bathroom, authorities said, he made a call to 911. He swore allegiance to the Islamic State terrorist group. He referenced the Boston Marathon bombing.
Crisis negotiators made contact with Mateen, who Mina said sounded "cool and calm" on the phone.
"He really wasn't asking for a whole lot, and we were doing most of the asking," the chief said.
Police did not immediately burst into the building, Mina said, because Mateen wasn't firing shots at the time and negotiators were still talking to him.
Before dawn, the conversations turned more dire. Police said Mateen talked about explosives and claimed he was wearing a bomb vest. "There was a timeline given," Mina said, and officials feared that more deaths were imminent.
Officers decided to break through a wall and enter the club with the tactical teams.
About 5 a.m., authorities tried to use an explosive device to blow a hole in the wall of a bathroom. It didn't work, so they used an armored vehicle to punch through. Mina said several people ran out, including Mateen, still armed.
Another gunfight ensued, and Mateen was killed. Asked if any of the tactical officers' bullets might have hit innocent victims, Mina said the circumstances of the standoff remained under investigation, but that no one else was in their path as they fired.
"Their backdrop was a concrete wall," he said.
Wounded fill hospital
Many of the wounded were taken less than a mile away to the Orlando Regional Medical Center.
In the emergency room, a surgeon quickly realized the staff on duty needed help. A pediatric surgeon arrived. So did vascular and orthopedic surgeons.
Technicians carted patients to operating rooms. They hurried to stanch blood flowing from bullet wounds in people's thighs, arms, backs.
Nine people were pronounced dead shortly after arriving at the hospital, several in critical condition or without vital signs.
Six trauma surgeons started operations within an hour. They had trained for this, running through trauma simulations every week.
The surgeries continued into Monday morning, when a total of 44 victims had been treated at the medical center. Six people had been discharged. All told, doctors had performed 26 surgeries, with more scheduled throughout the day.
No one else died after Sunday morning.
Police cars choked closed streets around Pulse as investigators searched the club Monday.
Officials had worked overnight to carry out the bodies from inside.
In Mateen's van, parked outside Pulse, they found an unidentified third weapon.
The FBI led the investigation as officers examined every inch of the 4,500-square-foot nightclub. Blood stains, bullet fragments, pieces of people and shattered walls. Every tiny bit that could lend clarity to the violence.
Nearly two hours away, in Fort Pierce, authorities searched Mateen's possessions for evidence that would point to motives for the shooting. His father said he thought his son was fueled by hatred for gay people.
Late Monday, the Orlando Sentinel reported that four regular Pulse patrons have said they saw Mateen in the nightclub multiple times before the night of the shooting.
President Barack Obama called Mateen a "homegrown" extremist.
ISIS took credit for the mass shooting, but Obama said Mateen seemed to have pledged allegiance to the group only at the last minute, and there was no evidence he was directed by anyone outside the United States.
Waiting for answers
In Orlando, news continued to trickle slowly to the families of the missing. The community rallied around survivors with vigils and signs, blood donations and warm meals. An Equality Florida online fundraiser had brought in more than $2.4 million by Monday evening.
An evening rally drew thousands to downtown Orlando and vigils in other cities, including in Tampa, were similarly packed.
Earlier, outside the Beardall Senior Center, volunteers used umbrellas and their bodies to shield relatives from more than a hundred reporters on the sidewalk.
Julissa Leal, 18, had driven 12 hours from Louisiana with her mom when she heard her brother, Frank Hernandez, was missing. He had been at the club with his boyfriend, who had been shot in the arm.
Just before 10 a.m., as Leal walked across the parking lot toward the senior center, she said she still didn't know anything.
"We don't know if he is in the hospital or in the other group of 50," she said.
About three hours later, the City of Orlando issued an alert naming eight other victims.
Last on the list was Frank Hernandez, 27 years old.
Times staff writers Ben Montgomery, Michael LaForgia and Josh Solomon and news researchers John Martin and Caryn Baird contributed to this report. Information from the Associated Press was used in this report.