When Omar Mateen finished pumping bullets into dozens of people sprawled on the dance floor inside Pulse nightclub on June 12, he walked toward the bathrooms where many patrons had hidden. It was just minutes after the Orlando police were called about the gunfire, and law-enforcement officers began descending on the club.
Four of them entered the building through one patio, while six others shot out a window to get inside. Among the 10 officers who went into Pulse, some had powerful military-style rifles and one had a shield. At least two had tactical experience.
Police fired at Mateen when he popped his head out of one the bathrooms. The shooter was now outgunned and outnumbered.
But then, police decided not to pursue him.
This account, based on interviews with law enforcement officials and witnesses, as well as public records, provides the most complete picture yet of law-enforcement response and Mateen's movements inside the club on the night of the attack.

The decision not to follow Mateen into the bathroom proved critical. Because Mateen was not subdued or killed sooner, wounded victims remained trapped inside the bathroom for hours, pleading for the police to rescue them. Emergency medical personnel did not enter the club to treat victims because it was deemed too dangerous. And during the final standoff, in which police initially failed to breach the club wall and struggled to make entry, Mateen apparently shot more victims, according to witnesses.The new details raise questions about how police and fire agencies responded to what became the deadliest mass shooting in modern history - and how the attack turned into a hostage standoff that lasted nearly three hours.
At least five people were alive in the bathrooms when the standoff began and ultimately died at the club, witnesses and relatives said. Three of these people - Deonka Drake, Eddie Justice and Alejandro Barrios Martinez - sent text messages from inside the club's bathrooms and were later among the dead.
Witnesses in the women's bathroom said Mateen killed at least three people during the final moments of the standoff, opening fire as SWAT officers were moving to breach the walls.
"They took too damn long for me," said Tiara Parker, 21, who was inside the bathroom. "If they had moved faster they would have gotten us out of there and everybody could have possibly lived."
In a lengthy interview, Orlando Police Chief John Mina defended the actions of officers inside the club and the rationale for not ending the attack sooner.
Mina said that because Mateen stopped shooting after he entered the bathroom, and he had hostages, the police did not pursue him.
"He went from an active shooter to a barricaded gunman," said Mina. "If he had continued shooting, our officers would have went in there."
How Orlando police responded to the shooting will be studied closely as other departments across the country try to prepare their officers for the next mass shooting.
The Justice Department, at the Orlando Police Department's request, is reviewing the law enforcement response.
Similar reviews have been launched after other attacks at movie theaters, schools and government installations. The examination of how authorities responded to the Pulse shooting will join a grim catalogue of assessments that sought to learn lessons from attacks in Aurora, Colo.; at the Washington Navy Yard; and at Virginia Tech.
In each of those mass shootings, officials found that they could do things better the next time.
"The highest priority is to eliminate the threat," said Dan Oates, who was the police chief in Aurora when a gunman opened fire in a movie theater, killing 12 and injuring scores more. Oates declined to comment on the Orlando shooting and the response there. He added: "If the best information is the shooter is on the fourth floor, you get to the fourth floor. If you run into the bad guy, you better be ready to deal with it."Gunshots and screams
The bloodshed at Pulse unfolded in a matter of minutes.
At 2:02 a.m., Mateen entered the club with his semi-automatic rifle at the ready and started shooting immediately, according to The Washington Post's timeline constructed from interviews and public records.
He fired repeatedly in the main room of the club, then moved toward the back room of Pulse, continuing to shoot. Clubgoers went running for hiding places and exits, jumping over the bodies of those already hit. Some played dead. The only sounds were gunshots and screaming.
Mateen was able to move around the space quickly. Not including an outdoor patio, the club contains less than 5,000 square feet.
Moments later, he returned to the main room. He fired at wounded people lying on the dance floor and reloaded his magazine.
Then he returned to the back room, shooting victims again. For a third time, he walked into the main room, changed magazines and fired at more people.
At 2:07 a.m., he headed to the restrooms and continued to shoot.
Angel Santiago described running directly into the one of the bathrooms with a friend after the shooting started in the club. Santiago estimated that there were about 15 to 20 people in there. Mateen entered shortly after and started shooting.
Parker said that when she saw Mateen come inside the women's room, his rifle jammed, so he used his handgun.
By 2:10 a.m., at least 10 officers had entered the club.
The first moments were filled with confusion as the police made their way through the dark club. One who entered through the east patio said he heard shots, while another said that was not the case.
A group of six officers, including Officer Brandon Cornwell, had entered the club by busting out a window. Cornwell said Mateen "was actively shooting."
Orlando officer Michael Ragsdale later said in his narrative to police that as he entered the back bar area from the patio, he saw two other officers shooting down a hallway.
"At that time I could not see what they were shooting at," he said.
There seemed to be a lull in gunfire, Mina said, and then Mateen apparently began shooting again, revealing to officers his location in the club. Mina said he thinks that officers shot at Mateen at about 2:17 a.m., the same time that emergency dispatchers received some of the last reports of gunfire. It was not clear whether Mateen fired at police during this encounter.
Mina said that once Mateen was barricaded in the bathroom, the shooting stopped, so police decided to hold their positions.
"If there had been additional shots, [police] would have heard," Mina said. "They were literally feet from the bathroom."
By almost 2:18 a.m., police seemed to have control of the club's main room, according to publicly released documents and interviews.
For the next three hours, though, the women's restroom turned into a terrifying scene as clubgoers, some of them suffering from multiple gunshot wounds, were trapped with Mateen.
One victim, Parker's cousin, 18-year-old Akrya Murray, described losing feeling in her arm. She later told a dispatcher, at 2:36 a.m., that she was losing her eyesight and feeling in her body.
In another exchange, a caller said "people are bleeding out in the bathroom."
At 2:35 a.m., another caller described "everyone in the bathroom groaning in pain." At 2:39 a.m., Eddie Justice texted his mother: "I am gonna die."
On the one-month anniversary of the Pulse nightclub massacre, Orlando Regional Medical Center employee Amanda Jane Saunders-Johnston takes a look at crosses honoring the 49 victims. Photo / AP
Meanwhile, Mateen was making contact with 911 and police. In a 2:35 a.m. call to an emergency dispatcher, he said he was the shooter in Orlando and pledged allegiance to the leader of the Islamic State.
In three other calls scattered over the next hour, each lasting between three and 16 minutes, Mateen talked with police negotiators. He said there was a vehicle outside the club with bombs and that he had a vest-the kind they "used in France."
"In the next few days, you're going to see more of this type of action going on," he said to a negotiator. While he was holed up in the bathroom, Mateen searched online for mentions of the shooting, according to law enforcement officials.
Police continued trying to free people from the club. At 4:21 a.m., officers pulled out an air conditioning unit from a dressing room window to let victims evacuate. Mina said eight people who had been hiding inside were saved.
As victims escaped through the window, they told officers that Mateen said he would put bomb vests on four people within 15 minutes.
Once they learned this, police decided they had to make a move, despite the potential consequences.
At 5:02 a.m., the Orlando police SWAT team and a hazardous device team from the Orange County Sheriff's Office began breaching the wall of the club. They tried to use explosives to bring down a bathroom wall so they could enter and rescue victims, but it didn't work.
The failed attempt probably signaled to Mateen that police were coming. Minutes passed as officers tried to ram the right opening into the club-an eternity during this kind of police assault, experts said.
During that time, witnesses said Mateen started killing people inside the bathroom.
"We were already at great risk, but . . . they made it worse," Parker said. "They put us at more risk."
Parker said she saw Mateen kill at least two people, possibly a third, in the women's bathroom. Based on photos of the victims that were published after the shooting, she identified two of them as Deonka Deidra Drayton and Tevin Eugene Crosby, whom she said were alive before police killed Mateen.
Patience Carter, another survivor who said she fled and hid in a bathroom stall with Parker, said that when police ordered people away from the wall as they prepared to breach, Mateen appeared to shoot several more people.
Using a Bearcat armored vehicle, authorities punched a hole between the two bathrooms, but they had picked the wrong spot. In a third attempt to get in, the tactical personnel created another hole in the men's room, and survivors started streaming out.
Mateen emerged from one of the openings and fired at the SWAT team. Parker said the fusillade was intense.
"I was getting burned up by the bullets bouncing from everywhere," Parker said, adding she could feel the heat from bullets flying past her.
At 5:14 a.m., police radio communications indicated that shots were fired. One minute later, those radio calls said that police had shot at Mateen and he was reported down.
When it was over, Mateen was dead. So was Murray, the 18-year-old who had called 911 saying she was losing feeling in her body. She was among the dozen or so dead in the bathrooms. Officials found no explosives or suicide vests.
Mina said 15 hostages held in one bathroom were freed and another three to five escaped from the other.
A passerby takes a photo of the Pulse nightclub. Photo / AP

Officers "followed their training"

In the aftermath of the shooting, law enforcement officials defended their actions. A. Lee Bentley III, the U.S. attorney for the Middle District of Florida, has said that the officers responding "should not be second-guessed."
Mina said this was not a typical active shooter situation. If Mateen had been in the open, he said, the officers would have shot at or arrested him. Instead, Mateen was already in the bathroom when he was first spotted.
"Officers followed their training in responding to active shooter incidents," Mina said.
Police say that during the standoff, they were continuously taking victims out of the club from the main room and bringing them to medical help outside.
Paramedics responding to the shooting, however, never came within 100 yards of the building during the attack and standoff that followed. They were "not equipped to handle an active shooter," according to Orlando Fire Department District Chief Bryan Davis, who served as incident commander that night.
Mina said that if this had been a college campus or mall, emergency fire and rescue personnel would have come into the building. But this was a relatively small building that police cleared quickly.
"There wasn't a need" for paramedics to enter the building, he said. Officers "were easily able to get people to aid."
After other shooting attacks in places like Aurora and Columbine, officials and experts have emphasised the importance of pursuing the attacker or attackers as quickly as possible.
"In light of experience from multiple victim shooting incidents in the past two decades, widely accepted police strategy is to attempt to quickly neutralise an active shooter - go to the shooter, and do not wait for special teams or special equipment or a large force for attack," concluded an independent report analysing the 2012 Aurora movie theater shooting at the city's request. "The longer the perpetrator is left to shoot, the more people may be killed or injured."
The Orlando police posted on their website last December - after two attackers who pledged loyalty to the Islamic State killed 14 people in San Bernardino, Calif. - that they had held regular training for active-shooter situations since 2000.
"Since law enforcement's focus is always to contain and stop an active shooter, in 2014, OPD modified its training to integrate the Orlando Fire Department," the statement said. "In this new training, which was taught in scenario-based exercises starting last spring and summer, rescue personnel respond to what we call "warm zones" (where contact with the shooter or shooters is not likely to occur) so they can quickly enter, locate, treat, and evacuate casualties."
Police officials investigate the back of the Pulse nightclub. Photo / AP
Authorities are continuing to investigate the handling of the shooting. Mina said officials do not know how many of the victims who were alive during the prolonged standoff later died in the bathrooms or how many had survivable gunshot wounds.
The Florida Department of Law Enforcement is investigating the officers who discharged their weapons; the agency declined to say specifically when during the event any of them fired shots, saying that information would be released when the investigation concludes.
During the initial encounters with Mateen and after the three-hour standoff that followed, authorities say a total of 14 officers fired their weapons at Pulse.
Orlando police say 11 of their officers fired, seven of them SWAT team members who fired at the end of the confrontation, killing Mateen. Three Orange County sheriff's deputies also fired.
Mina said he didn't know if law enforcement had killed anyone other than Mateen in friendly fire.
Chris Voss, a former FBI SWAT team member and hostage negotiator, said that the decision not to follow Mateen into the bathroom was a gamble, but one that was understandable.
"Cops are paid to take risks but not stupid risks," he said. "This is not military combat where there are acceptable casualties on both sides. Law enforcement doesn't have that conversation. No casualties are acceptable."
Voss said that "buying time increases the likelihood of a successful assault" and can often save more lives.
The rule for law enforcement, he said, is, "Don't make things worse."
"We don't want cops to be cowboys," Voss said. "I see cops going down and things being worse. Play the odds and step back."
Mina said there will be lessons learned, but his officers did the best they could with the information they had at the time.
"I have no regrets in the decisions that my officers and commanders on the ground made and I have no regret with the decision I made either," he said.