At least four regular customers at Orlando's Pulse nightclub said they saw gunman Omar Mateen at the venue prior to his June 12 attack, which left 49 dead.
The Orlando police say they have no information about previous sightings, according to the Orlando Sentinel.
One customer said he had seen Mateen at Pulse a dozen times.
“We didn't really talk to him a lot, but I remember him saying things about his dad at times,” Ty Smith told the Sentinel. “He told us he had a wife and child,” Ty Smith told the Sentinel.
Mateen opened fire around 2 a.m. June 12, killing 49 and injuring 53. He was killed in a gun battle with the Orlando Police Department several hours later.
Mateen held a number of people hostage during the attack. He proclaimed his allegiance to Islamic State (ISIS) and the brothers who organized the Boston Marathon bombing in 2013.
Mateen had worked as a security guard for G4S since 2007 and passed all of the checks required in Florida to own a firearm.
He applied for a state security guard license, which is required to carry a gun, was a U.S. citizen, and did not have a criminal record. He also passed a psychological test.
Mateen purchased two weapons at St. Lucie Shooting Center, a 9mm semi-automatic pistol and a .223-caliber assault rifle.
Edward Henson, who owns the store, said he vaguely recalled Mateen.
“He's a nobody,” Henson told the Sentinel. “He's a customer. He came and purchased his guns, and he left.”
Mateen’s father, Seddique Mir Mateen, said the attack has devastated the family.
“If he was alive we could ask why he did this. He never showed any signs of mental illness or links to extremist groups,” he told the Guardian. “No father or family should ever have to go through this kind pain.”
“I don’t know if he had any connections to ISIS,” he added.
Seddique Mateen rejected the idea that he was in any way responsible for his son’s crime.
“You can have a child, send them to school and hope they grow up to be responsible adults,” he told the Guardian. “What he does and what he did, he was an adult.”
Seddique Mateen also posted a video online in Dari, a language spoken in Afghanistan, condemning the shooting. However, he went on to suggest that it was up to God to enact “punishment” against gay people.