Omar Mateen ‘cool and calm’ during Orlando slaughter

The gunman behind the worst-ever US mass shooting was “cool and calm” as he talked to police during his bloody rampage that left 49 people dead and 53 injured, according to Florida police.

Further details of the horrific attack on the gay nightclub Pulse in Orlando on Sunday morning emerged yesterday as US law enforcement officials shed more light on why Omar Mateen (29), a US citizen of Afghan descent, might have carried out the massacre.

As the almost three-hour hostage situation unfolded at the club, Mateen spoke to police by telephone and said that he was carrying out the attack for the leader of Islamic State, the Middle-Eastern militant extremists, and pledged allegiance to the radical group.

FBI director James Comey said that it was "not entirely clear" what terrorist group Mateen, who worked as a security guard two hours away from Orlando in Port St Lucie, aspired to support as he offered contradicting motives to a 911 telephone dispatcher.

He claimed solidarity with the Tsarnaev brothers who carried out the 2013 attacks on the Boston Marathon bombing and with a Florida man who had killed himself in a suicide attack in Syria for al-Nusra Front, a group aligned with Islamic State, which is also known as Isis and Isil.

“The bombers at the Boston Marathon and suicide bomber from Florida were not inspired by Isil, which adds a little bit to the confusion about his motives,” Mr Comey said at a briefing, using the other acronym used by the Obama administration for Islamic State.

Homegrown extremism

President

Barack Obama

said that there was no clear evidence at this stage that Mateen’s attack was part of a larger plot or that he had been directed by the militant group, drawing parallels with the attack by an Islamic State-inspired couple in

San Bernardino

,

California

last year.

“As far as we can tell right now, this is certainly an example of the kind of homegrown extremism that all of us have been so concerned about for a very long time,” he said.

Speaking to reporters in the Oval Office, the US president said it appeared Mateen had been inspired by extremist information available on the internet.

“One of the biggest challenges we are going to have is this kind of propaganda and perversions of Islam that you see generated on the internet, and the capacity for that to seep into the minds of troubled individuals or weak individuals,” he said.

The FBI chief defended the bureau’s handling of two investigations, in 2013 and 2014, when Mateen was interviewed by agents about statements he made to work colleagues about having ties to terrorism and, later, about his links to the Florida bomber.

There was nothing his agents “should have done differently,” said Mr Comey, outlining the FBI’s efforts that ultimately led the agency to rule Mateen out as a threat.

Panicked texts

As police released the names of the victims caught up in the massacre, the mother of one revealed the panicked text messages sent by her son as he was trapped in the nightclub.

“Mommy I love you,” Eddie Justice (30) wrote in one text. “In club they shooting.”

Minutes later, he asked his mother to call the 911 emergency line.

“Trapp in bathroom,” he wrote. “He’s coming. I’m gonna die.”

The victims, who were among a 300-strong crowd at a Latin-themed night, ranged in age from 19 to 50 and included a bouncer, a dancer and an accountant.

Terry DeCarlo, executive director of the LGBT Centre of Central Florida, told The Irish Times that Orlando's gay community was struggling with a mix of emotions.

“People don’t know what to think,” he said. “They don’t understand why something like this has happened in their city. It is a lot of shock and anger and sadness right now.”