The gunman who shot dead at least 49 people in Orlando was reportedly a regular at the gay nightclub and used dating apps for gay men. A regular club-goer, Ty Smith, told the Orlando Sentinel that he had seen Omar Mateen, the shooter, at the club at least a dozen times. “Sometimes he would go over in the corner and sit and drink by himself, and other times he would get so drunk he was loud and belligerent,” he said, adding that Mateen spoke about his father at times.

Another regular at Pulse, Kevin West, told the Los Angeles Times that Mateen, who was killed by security forces in the shooting, had messaged him sporadically for a year on a gay chat app. Other club-goes told local media and MSNBC that he had been using multiple gay apps, such as Grindr, with mutual acquaintances to “hook up”.

The bloodshed in which at least 49 were killed and 53 others wounded was the deadliest mass shooting in United States history. Chief of the Federal Bureau of Investigation James Comey said the agency was “highly confident” Mateen had been “radicalised” through online propaganda. The 29-year-old assailant had pledged allegiance to the Islamic State on a 911 call before going on a rampage in the nightclub.

US authorities have claimed there was no direct link between the extremist outfit and the US-born son of Afghan immigrants. President Barack Obama also said there was no evidence that Saturday’s mass shooting was part of a larger plot hatched abroad, Reuters reported. “At this stage, we see no clear evidence that he was directed externally,” Obama said.

However, Mateen had been investigated by the FBI in 2013, after claiming to be a member of Islamist group and Lebanese political party Hezbollah and of having family ties to the al Qaeda. He was interrogated by the FBI chief, who had undercover agents trail Mateen for ten months. He was investigated again in 2014, after it was found he had links to man who became a suicide bomber in Syria, The Telegraph reported.