The FBI is investigating the shooting as a possible ideologically motivated act of terrorism, the sources said.

The killer, who is a US citizen from Senegal, had a Quran in his car and clothing described as Islamic garb when he opened fire on Buford’s Backyard Beer Garden near the University of Texas-Austin campus, according to sources familiar with the investigation.

The gunman has a history of arrests in Texas, and is believed to have lived in New York City from 2000 to 2008, the sources said.

“Obviously it’s still way too early in the process to determine the exact motivation but there were indicators on the subject and in his vehicle that indicate potential nexus to terrorism, Alex Doran, acting Special Agent in charge of the FBI’s San Antonio office, told reporters in an update Sunday.

The attack happened about 2 a.m. — closing time — as hundreds of people were leaving the popular nightspot.

A large SUV was spotted traveling around the block several times when he stopped in front of the bar and began shooting out of the front window with a pistol, hitting patrons out on the front patio, according to Austin Police Chief Lisa Davis.

He then parked the car, got out and began shooting at people walking by on the street, the chief said.

Police confronted the shooter within less than a minute of the first gunshot at an intersection on 6th Street and shot him, cops said.

Two victims and the shooter died at the scene. First responders rushed 14 other patients to nearby hospitals, three of whom were in critical condition.

No one has been identified so far.

“Our hearts go out to the people that are victims of this and I want to reiterate my thanks to our public safety officers and officials that so rapidly were on the scene, they definitely saved lives,” Austin Mayor Kirk Watson said.