Police revealed details Monday of what it took to save "dozens and dozens" of lives from a shooting and hostage siege at an Orlando gay nightclub, as the death toll was revised to 49 and more families of victims were notified.
FBI special agent Paul Wysopal said 48 victims have been identified and 24 of their families have been notified. An earlier death toll of 50 had included the deceased shooter, he said.
A day after the massacre inside the Pulse nightclub in central Orlando, all of the bodies had been removed. Investigators said most of the victims were found in the club's lounge area, bar and bathrooms.
Police chief John Mina said officers acted "heroically" in their first response to the gunfire, which erupted in the early hours of Sunday as the club's Latin-themed night was drawing to a close.
"Dozens and dozens of people were saved" from the mayhem as police rushed into the building and engaged in a gun battle with Omar Mateen, a 29-year-old Florida resident and US citizen.
After Mateen moved deeper into the club, he barricaded himself in a bathroom with "four to five" hostages for several hours, Mina said. Between 15 and 20 people were hiding in a separate, opposite bathroom.
At one point Mateen, whose parents are immigrants from Afghanistan, called 911 emergency operators and declared "an allegiance to Islamic State," Mina said.
Al-Bayan radio, which broadcasts inside Islamic State territory in Iraq, Syria and Libya, claimed Monday that the attack was carried out by a "soldier of the caliphate."
"God helped Omar Mateen" carry out an attack against "crusaders," said the morning broadcast on what is seen as the sanctioned station of the extremist group. It described Pulse as a "sodomite night club."
US investigators said they have not found a direct link to the terrorist group.
Mateen was "cool and calm" while on the phone with hostage negotiators, Mina said. The shooter said he was "wearing a vest" and had explosives with him, the police chief said.
Three hours after the worst mass shooting in US history began, the decision was made to breach the wall of the bathroom - first unsuccessfully with explosives and then with an armoured vehicle - because Mina felt that "a further loss of life was imminent."
Mateen then came out of the bathroom and shot at officers, who returned fire and killed him.
The FBI-led investigation followed up on more than 100 leads sent in by the public overnight.
Mateen legally purchased two firearms used in the attack - and AR-15 assault rifle and a handgun - within the last week, authorities said. A third gun was found in his van parked outside the club.
The FBI said Mateen was investigated twice by the agency - in 2013 and then again in 2014 - for a possible Islamist militant connection, but no conclusive evidence was found against him.
Mateen was employed as a private security guard with GS4 since 2007. As part of his job he carried a weapon, the company said.
Mateen's ex-wife described him as being violent and mentally unstable during their relationship, but said that he never expressed Islamist militant leanings.
Sitora Yusufiy told reporters from her home in Colorado that she met Mateen through an online dating service: "In the beginning he was a normal being, who loved to joke, loved to have fun."
But within a few months of their 2009 marriage he became violently abusive toward her. Yusufiy described him as bipolar and said He kept her "hostage" and isolated. Their divorce was finalized in 2011.
His father, Seddique Mateen, said in several interview that his son's actions were not related to his religion. He said Omar had been angered after seeing two men kiss in Miami several months ago.