FBI agent Ron Hopper explained the decision not to release the audio of the Orlando victims' 911 calls June 20, saying it would be too painful for those affected by the massacre at Pulse nightclub. However, the agency did release a partial transcript of shooter Omar Mateen's 911 call. (Reuters)

As he talked on the phone with dispatchers and crisis negotiators from the bathroom of the Pulse nightclub in Orlando, gunman Omar Mateen said that a vehicle outside contained explosives and that he would “ignite it” if police tried to “do anything stupid,” according to a partial transcript released by the FBI on Monday. He told those on the other end of the phone that he “did the shootings” and he vaguely threatened more attacks.

“In the next few days,” he said, “you’re going to see more of this type of action going on.”

The transcript — even though it does not seem to account for every conversation — provides the most thorough look yet at precisely what Mateen, 29, told police as he holed up inside a bathroom at Pulse, keeping more than 15 people from fleeing to safety after he had shot others. It shows that he spoke of religion and explosives and told negotiators to tell U.S. government officials to stop bombing Syria and Iraq.

The investigation of what prompted Mateen to carry out the attack that killed 49 people and wounded dozens more before Orlando police SWAT team members moved in and fatally shot him is a little more than a week old, and many questions remain unanswered. Investigators do not know, for example, how many clubgoers might have been wounded by police fire in the chaotic encounter, nor do they know Mateen’s reasons for attacking the popular LGBT nightspot.

“What I can tell you is that while the killer made these murderous statements, he did so in a chilling, calm and deliberate manner,” FBI Assistant Special Agent in Charge Ron Hopper said at a news conference Monday.

Hopper said that the bureau’s investigation “may last months or even years” and that investigators had conducted more than 500 interviews and collected hundreds of pieces of evidence. He said agents think Mateen “was radicalized domestically,” rather than directed by any foreign terrorist group, although they are looking at “myriad” things to determine a precise motive.

As it released the partial transcript, the FBI also provided a more detailed timeline of law enforcement’s hours-long encounter with Mateen. The first call about multiple shots being fired at the club came at 2:02 a.m., and two minutes later, more police officers arrived. Officers from various agencies entered the club at 2:08 a.m., and at 2:18 a.m., the SWAT team was called in.

At 2:35 a.m., Mateen made his first 911 call from the bathroom.

“In the name of God the Merciful, the beneficial,” he said, in Arabic, according to the transcript.

“What?” the call taker responded.

“Praise be to God, and prayers as well as peace be upon the prophet of God. I let you know, I’m in Orlando and I did the shootings,” Mateen said.

“What’s your name?” the call taker asked.

“My name is I pledge of allegiance to Abu Bakr al-Baghdadi of the Islamic State,” Mateen said.

Law enforcement and other officials have said previously that Mateen pledged his allegiance to the Islamic State during one of his calls to police, and he posted messages on Facebook doing the same, although, initially, they redacted references to the terrorist group and its leader in the transcript. That decision drew critical questions from reporters at a news conference Monday, as well as from House Speaker Paul D. Ryan (R-Wis.) and Florida Gov. Rick Scott (R), and the Justice Department later reversed its decision.

“Unfortunately, the unreleased portions of the transcript that named the terrorist organizations and leaders have caused an unnecessary distraction from the hard work that the FBI and our law enforcement partners have been doing to investigate this heinous crime,” the Justice Department and the FBI said in a joint statement. “As much of this information had been previously reported, we have re-issued the complete transcript to include these references in order to provide the highest level of transparency possible under the circumstances.”

In a statement before the department reversed its decision, Ryan said: “Selectively editing this transcript is preposterous. We know the shooter was a radical Islamist extremist inspired by ISIS. We also know he intentionally targeted the LGBT community. The administration should release the full, unredacted transcript so the public is clear-eyed about who did this, and why.” Scott called it “another example of not focusing on the evil here” during an interview on Fox News Channel.

“Why wouldn’t you release everything?” Scott said. He went on to mention the victims at Pulse as well as Steven J. Sotloff, a Miami journalist executed by the Islamic State, a group also known as ISIS and ISIL, and said that “at some point, we’re going to get a president who’s going to say ‘I care about destroying ISIS.’ ”

When asked why he thinks references to the Islamic State were removed from the transcript, Scott said, “It sure appears that they don’t want to talk about that ISIS was involved.” During remarks about the shooting, President Obama and FBI Director James B. Comey have repeatedly mentioned the gunman’s pledge of allegiance to the Islamic State.

A. Lee Bentley III, the U.S. attorney for the middle district of Florida, said authorities were releasing only part of the transcripts “to avoid re-victimizing those who were in the Pulse nightclub.” They did not release any audio of the conversations.

“We wanted to release the transcripts at this time so the public could have a better idea of the timeline … and also so that you would have a better idea of what the law enforcement officers on the ground were dealing with when they made the decision to enter the nightclub,” Bentley said.

Hopper said authorities also did not want to “give credence to individuals who have done terrorist acts in the past.”

“We’re not going to propagate their violent rhetoric,” he said.

Investigators also have explored claims that Mateen had used a dating app to seek men and had been to Pulse before the shooting, and officials have said they are investigating the crime as one of both terrorism and hate.

Attorney General Loretta E. Lynch told CNN on Sunday that Mateen “didn’t get into” his thoughts about gay people during the calls, and that the partial transcript shows no such discussion. Hopper said that allegations about Mateen being gay were “still being vetted out” and that investigators had reached no conclusions.

Comey has said previously that there were three 911 calls involving Mateen. The gunman, he has said, called 911 about half an hour after his rampage began, then hung up. He then called back and spoke briefly to a dispatcher before hanging up again, at which point the dispatcher called Mateen back, the FBI director has said. The dispatcher and Mateen spoke briefly on that last call, Comey has said.

The FBI said Monday that Mateen had three calls with crisis negotiators — the first at 2:48 a.m. lasting nine minutes, the second at 3:03 a.m. lasting 16 minutes and the third at 3:24 a.m. lasting three minutes. In those calls, Mateen “identified himself as an Islamic soldier,” the FBI said, and told the negotiator “to tell America to stop bombing Syria and Iraq.” The FBI said Mateen claimed that was why he was “out here right now.”

Mateen also claimed there was “some vehicle outside that has some bombs,” and threatened, “You people are gonna get it, and I’m gonna ignite it if they try to do anything stupid,” according to the FBI transcript. He also said he had a vest like the kind “used in France.” Authorities ultimately did not find any explosives.

The calls came after Mateen twice exchanged gunfire with police officers at Pulse and fled to a bathroom, authorities have said. Orlando police officials have said the gunfire stopped after he entered that bathroom, and negotiations began. All the while, they have said, officers worked to free what hostages they could, including those hiding in dressing rooms.

Some of those trapped in the bathroom with Mateen have described his phone calls previously, and law enforcement officials have noted other contacts. Mateen exchanged text messages with his wife and had at least one phone call with an acquaintance, law enforcement officials have said. The details of that call and those exchanges, though, are unclear, and the FBI has not said precisely how many calls Mateen made or to whom. The transcript seems to leave out what happened during large stretches of time.

During the news conference, authorities repeatedly pushed back against questions about the law enforcement response at the club and whether officers could have acted more aggressively to stop the gunman. The officers who responded during the attack “should not be second-guessed,” Bentley said. “They performed valiantly during those early morning hours. Lives were saved because of their heroic work.”

John W. Mina, the Orlando police chief, said that he thinks “there was this misconception that we didn’t do anything for three hours,” and emphasized that police officers were continuing to work, an effort that included heading back into the club to rescue people. He declined to say whether officers had inadvertently wounded bystanders in the encounter but said Mateen bore responsibility for what transpired.

“That’s all part of the investigation, but here’s what I will tell you: Those killings are on the suspect and the suspect alone, in my mind,” Mina said.

Dorian Wayne, who was in the club that night, said he thinks police “could have run in and shot” Mateen, but said he is sympathetic to the tough decisions law enforcement officers had to make.

“I feel for the people who were in there and didn’t get the proper help that they needed,” Wayne said. “But at the same time, I understand the cops — they’re human.”

Negotiations ultimately broke down with Mateen about 5 a.m., authorities said, and SWAT officers scrambled to break holes in the walls to the bathroom and free those held captive. The FBI said Monday that about 12 minutes after they started doing so, they received reports of shots being fired. Mateen eventually came out one of those holes, police have said, where SWAT officers killed him in a final gun battle.

His body — which was transported separately from Pulse and held in a different building from the one that held the remains of the victims — has been released from the Orange County Medical Examiner’s Office, authorities confirmed Monday.

Abigail Hauslohner and Arelis Hernandez contributed to this report.