The FBI had looked into Orlando shooter Omar Mateen twice in the past as a “known quantity,” but apparently found nothing worth further investigation, even though now it’s believed Mateen may have had ties to Islamic extremism.

A senior law enforcement source told The Daily Beast the FBI opened files on Mateen in 2013 and 2014, declaring him a “person of interest.” There was even an active investigation on Mateen, whose parents are from Afghanistan, but again, law enforcement didn’t seem to find anything particularly noteworthy.

“He’s a known quantity,” the law enforcement source said. “He’s been on the radar before.”

The fact that Mateen had been on the FBI’s radar before was perhaps the reason why authorities were able to so quickly say Mateen had “leanings” toward Islamic terrorism.

This connection to Islam was disputed immediately by Mir Seddique, Mateen’s father, who told NBC News that the massacre “has nothing to do with religion.”

But Mir Seddique also noted that a couple months prior to the shooting, Mateen had been severely angered by the sight of two men kissing.

Although the attack has not been linked to Islamic State at this point, the group did call for increased terror in advance of Ramadan.

“Ramadan, the month of conquest and jihad. Get prepared, be ready … to make it a month of calamity everywhere for the non-believers … especially for the fighters and supporters of the caliphate in Europe and America,” Abu Mohammed al-Adnani, ISIS spokesman, said in May.

Mateen burst into gay club Pulse in Orlando at 2:00 a.m. and opened fire with an AR-15 and a handgun. He then took hostages. At about 6:00 a.m., a SWAT team took him out in a gun battle.

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