A mass shooting in downtown Austin, Texas, early Sunday left three people dead and 14 wounded, and the FBI is investigating it as “potentially an act of terrorism.”

The suspect, identified as 53-year-old Ndiaga Diagne, a naturalized U.S. citizen born in Senegal, was killed by police after opening fire outside Buford’s Backyard Beer Garden and nearby streets.

Diagne was reportedly wearing clothing referencing “Allah” and an Iranian flag, and authorities are investigating his digital footprint, communications, and possible radicalization.

Officials believe he acted alone, with mental health also being examined, and federal and local authorities continue executing search warrants and interviewing associates, Fox News has reported.

The shooting occurred in a busy entertainment district, and a Victim Services Unit hotline has been established for families seeking information.