Theman who shot eight people to death at a Dallas-area shopping mall over the weekend harbored neo-Nazi sympathies but appeared to have targeted his victims at random, without regard for race, age or sex, Texas law enforcement officials said on Tuesday.
Authorities also disclosed new details about the gunman's background. They said he was discharged from US Army basic training 15 years ago, had once worked as a private security guard and suffered from an unspecified mental illness.
The suspect, previously identified as Mauricio Garcia, 33, opened fire with an AR-15-style rifle on Saturday at the crowded Allen Premium Outlets mall in Allen, Texas.
The carnage ended about four minutes later when a lone police officer confronted and fatally shot Garcia in a swift response that "undoubtedly saved countless lives, said Hank Sibley, a regional director of the Texas Department of Public Safety.
The officer was not publicly identified.
The eight people slain in the attack included three children - two young sisters as well as a 3 year old boy from a different family whose parents were also killed. In addition, 10 other people, ages 5 to 61, were wounded.
Investigators recovered three firearms, including the murder weapon, from the gunman's possession, and five more from his vehicle, and Garcia had legally obtained all eight guns, according to Sibley.
"The big question we're dealing with now is: what's his motive? Why did he do this? We don't know," Sibley said at an afternoon press conference, adding investigators believe Garcia acted alone.
From evidence reviewed so far, including clothing patches and tattoos, "we do know that he had neo-Nazi ideation," but it was too early in the investigation to say whether the shooting could be considered an act of domestic terrorism, Sibley told reporters.
"To me, it looks like he targeted the location rather than a specific group of people," Sibley said. "He was very random in the people he killed. It didn’t matter the age, race or sex. He just shot people, which is horrific in itself."
The assailant had enlisted in the Army in 2008 but was dischargedbefore completing basic training over "some questions about his fitness for duty," Sibley said.
Garcia, who had no criminal history before Saturday's shooting, also had once obtained a state security license, since expired, and worked as a security guard for several firms some time ago, Sibley said.
Authorities have given few details about the nature and extent of Garcia's neo-Nazi sympathies.
Multiple news outlets have reported in recent days that the gunman left behind a social media profile filled with white-supremacist ideology, praise for Hitler and diatribes vilifying racial minorities and women.
At the time of the shooting, Garcia also wore a patch bearing an "RWDS" insignia, a symbol associated with violent right-wing extremists, including the Proud Boys, according to news media organisations. RWDS is an acronym known to stand for "Right Wing Death Squad."
The author behind some of the posts under investigation repeatedly suggested he was of Hispanic heritage and as recently as last month included a post saying that "white people and Hispanics have a lot in common," the New York Times reported.