Diagne, originally from Senegal, arrived in the United States in 2006 and was a naturalized American citizen.
The attack occurred just before 2:00 a.m. near Buford's Backyard Beer Garden in the entertainment district of Sixth Street. According to Police Chief Lisa Davis, the suspect drove past the establishment several times in his SUV before opening fire with a pistol from the vehicle at people outside. He then parked, exited with a rifle, and continued shooting until he was taken down by the officers.
The FBI is investigating the case as a possible act of terrorism after finding "evidence" on the attacker and his vehicle, according to Acting Special Agent Alex Doran from the San Antonio office. Among the analyzed items is a shirt with the phrase "Property of Allah" and a design featuring the Iranian flag. Mayor Kirk Watson praised the swift police response, while the University of Texas confirmed that members of its community were among those affected.