Niagara Gazette — "We're not making any assumptions by that. We're going to keep an open mind and an open investigation. We will go where the facts lead us," Army Secretary John McHugh said, explaining that "possible extremist involvement is still being looked at very, very carefully."
Investigators were also looking into Lopez's psychological background. He had sought help for depression, anxiety and other problems, military officials said.
"We have very strong evidence that he had a medical history that indicates unstable psychiatric or psychological condition," Milley said. "We believe that to be a fundamental underlying cause."
Investigators searched the soldier's home Thursday and questioned his wife, Fort Hood spokesman Chris Haug said.
Lopez apparently walked into a building Wednesday and began firing a .45-caliber semi-automatic pistol. He then got into a vehicle and continued firing before driving to another building. He was eventually confronted by military police in a parking lot, Milley said.
As he came within 20 feet of a police officer, the gunman put his hands up but then reached under his jacket and pulled out his gun. The officer drew her own weapon, and the suspect put his gun to his head and pulled the trigger, Milley said.
Lopez grew up in Guayanilla, a town of fewer than 10,000 people on the southwestern coast of Puerto Rico, with a mother who was a nurse at a public clinic and a father who did maintenance for an electric utility company.