Texas mall shooting updates: What police found after search warrant issued
Eight people were killed in the attack.
Eight people were killed and seven others were injured when a gunman opened fire at an outdoor mall north of Dallas, Texas, on Saturday afternoon, officials said.
The alleged gunman died after a confrontation with police at the Allen Premium Outlets, police said.
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Shooter killed at the scene
The shooter was killed at the scene, police said.
Allen Police Department Chief Brian Harvey said at a press briefing that an officer was at Allen Premium Outlets on an unrelated call when he heard gunshots and located the shooter who was then "neutralized."
"We are asking for the public's help if you are a witness," Harvey said.
Suspect had history of mental health problems: Sources
Preliminary information developed during the investigation indicates the suspect was in the U.S. Army in 2008 and was "removed due to mental health concerns," law enforcement sources briefed on the probe tell ABC News.
In addition to the insignia on the shooter's equipment that suggested a right-wing extremist ideology, investigators have found social media accounts connected to the suspect that reveal hundreds of postings and images, including writings with racially or ethnically motivated violent extremist rhetoric, including neo-Nazi material and material espousing the supremacy of the white race, the sources said.
None of the subject's postings analyzed to date were liked or shared by other users nor were there any public comments, according to the sources. The suspect's account did not contain any friends or associates that were publicly visible, the sources said.
Investigators have determined the suspect had no criminal history and opened fire with a semi-automatic rifle, according to the sources. The shooter was equipped with a ballistic vest, numerous magazines and additional handguns, the sources said.
-ABC News' Josh Margolin