ORLANDO — The man who shot and killed 49 people early Sunday morning at the Orlando, Florida, LGBT bar Pulse, may have also planned to attack other gay-friendly locations in and around the Orlando area, a law enforcement source said Monday.

The source said Omar Mir Seddique Mateen’s online research and social media activity indicated an interest in LGBT clubs and destinations, suggesting he may have been planning to attack alternate locations instead of or in addition to the one he chose.

He also did online research into popular tourist destinations that are part of Disney World’s sprawling properties in Florida, though it’s unclear whether he considered any part of the iconic theme park or its properties as a target.

“He did show an interest in other locations as potential targets,” the source said.

One potential target was the Revere at the M, a club that opened in December at a gay-friendly boutique hotel about 8 miles from the shooting scene, the source said.

Late Sunday, the Revere announced on its Facebook page that it was permanently closing and would host only private events and conferences.

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A dancer at Revere was one of the victims killed Sunday in the most deadly mass shooting in U.S. history, the club also said on its Facebook page.

Mateen, 29, who was born in New Hyde Park, worked for the security company G4S in and had received firearms training.

The source said Mateen bought the weapons he used — an AR-15 assault rifle and a handgun — at the St. Lucie Shooting Center in Port St. Lucie and had attempted to buy body armor before the attack.

The store’s owner, Ed Henson, said Monday that Mateen legally purchased the guns and had two security licenses — one to carry a weapon, The Associated Press reported. Henson, who used to work for the New York Police Department and lived in Oceanside and Baldwin, said he was sorry this “evil person” bought the guns from his store.

On Monday, law enforcement agencies retraced Mateen’s final days and hours before he opened fire around 2 a.m. at the club during its popular Latin night event.

They seized computer hard drives and other electronics from his condo in Fort Pierce and at the homes of relatives in Port St. Lucie, said the federal law enforcement official with knowledge of the investigation into the shooting.

The shooter’s father, Seddique Mir Mateen, called his son’s massacre “the act of a terrorist” and apologized for his actions. “I condemn what he did,” he told reporters assembled outside his Port St. Lucie home.

President Barack Obama, who will travel to Orlando on Thursday, called Mateen, who lived as a child in Flushing, Queens, and in Westbury, an example of “homegrown extremism.”

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FBI Director James Comey on Monday said the FBI investigated the shooter in 2013 for 10 months after he expressed support for terrorism.

But his views were often at odds, like supporting both al-Qaida and its enemy Hezbollah.

On Sunday, Mateen made a 911 call during the attack, where he expressed loyalty to the Islamic State, solidarity with the brothers responsible for the Boston Marathon bombings and support for a suicide bomber who died in the name of the al-Nusra front, which is at odds with the Islamic State, Comey said.

Sen. Chuck Schumer (D-N.Y.) said an FBI briefing showed there were no ties from Mateen to ISIS and all evidence points to a classic “lone wolf.” Schumer, speaking Monday in Freeport, called on Congress to pass a law that would ban anyone under FBI investigation or on a terrorist watchlist from purchasing guns.

Meanwhile, the FBI continued to investigate Mateen’s links to known jihadists with ties to the Port St. Lucie and Orlando areas, including former associates of Moner Mohammad Abusalha, the first American-born terrorist to carry out a suicide bomb attack in Syria, the source said.

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Abusalha worshipped at the Islamic Center of Fort Pierce, where Mateen went several times a week, according to other worshippers and a law enforcement source.

The FBI is not looking at the center as a genesis of Mateen’s radicalization, said the source, adding that the agency is aware of religious pilgrimages Mateen made to Saudia Arabia in 2011 and 2012.

The source said Monday the FBI has uncovered evidence showing Mateen “expressed admiration” for and showed a particularly acute interest in the Tsarnaev brothers, who carried out the Boston Marathon bombings in 2013.

“He was influenced by various sources,” the source said.

Ahmed Khan recalled seeing Mateen come to the prayer center, often with a toddler in tow, who he said was his son. Mateen’s sisters, father and other relatives also regularly visited the center.

“He was devout, certainly,” said Khan, of Fort Pierce. “He often came to pray when he wasn’t working. He had his son with him. He seemed very peaceful.”

People across the country and around globe gathered to mourn as officials released the identities of all 49 victims.

“Right now it’s time to grieve for each family member that either lost a loved one or still has somebody in the hospital injured,” Florida Gov. Rick Scott said.

In Orlando, volunteers handed out food or water at the family information center. Others sat and prayed with those waiting for answers.

Lines grew at the donation site of the One Blood nonprofit in southeast Orlando to the point that they had to turn people away and take their information to call them back by appointment.

Ceci Santiago was among those who left their information.

“I never donated blood, but I need to do it because people need help,” said Santiago, 25, a native of Puerto Rico who moved to Orlando a year ago. “Whatever I can do to help people.”

Police on Monday described a chaotic scene as gunfire erupted in the busy club full of about 300 patrons.

An air conditioning unit was knocked free to provide a way out for a small group and the police used explosives to punch out escape holes after Mateen said he had four bomb vests for hostages and one for himself that he planned to use.

Orlando Police Chief John Mina said the incident began just before 2:09 a.m. when an off-duty Orlando police officer working security heard shots from the front entrance and responded, exchanging gunfire with Mateen.

Minutes later two other officers arrived on scene and the three followed Mateen inside, again trading shots until the shooter forced his way into a women’s bathroom where a group was hiding, Mina said.

Police began evacuating the nightclub and rescued people trapped in a men’s room.

For the next three hours, the shooting stopped as a negotiator talked with Mateen, who had called 911. Rescues continued during the standoff while Mateen pledged his “allegiance to the Islamic State,” Mina said.

The trapped customers helped police rescue them by calling 911 and texting friends outside the club where they were hiding. “The communications staff is telling us where they’re at after getting the calls,” Capt. Mark Canty said. “During that 3-hour period we’re actually rescuing people, probably about 50 people.”

Four people were freed when officers outside helped knock an air conditioner and part of a wall loose as those in the club pulled from the inside.

After Mateen told police he would detonate the vests in 15 minutes, the Orange County Sheriff’s bomb squad detonated explosives to knock holes in the walls to evacuate the rest of the people still trapped inside. A battering ram finished the job.

“We believed danger and future loss of life was imminent,” Mina said. “So that’s why we decided to make entry.”

As dozens of people began to escape, Mateen came outside firing and was killed by gunfire from SWAT members, he said.

“He wasn’t jubiliant,” Mina said. “For someone who had shot all of these people he seemed very calm.”

Officials said 39 people were found dead in the club, while nine died in ambulances and two people died on the street outside the club. Another 53 people were injured.

One officer, Michael Napolitano, was hit in his Kevlar helmet by a bullet but was not seriously injured.

It is not yet clear if any of the injured or dead patrons were hit by police bullets and autopsies continued Monday at the Orange-Osceola Medical Examiner’s Office in south Orlando where forensic pathologists from other medical examiners’ office are assisting.

The autopsies are expected to be completed Tuesday, according to county Public Information Officer Carrie Proudfit.