The shooting left four dead, including the gunman, and sixteen other military personnel injured.
The injured included John Arroyo, a graduate of Whittier High School.
Arroyo earned his degree from Campbell University, a Baptist school in North Carolina. He is a man of strong religious faith, which is shown on his Facebook profile.
A close friend told the Whittier Daily News, which first reported the story, the injured lieutenant was shot in the neck. He is alert and responsive, but may lose his voice box, the newspaper reported.
Spc. Ivan Lopez apparently walked into a building at the Texas military base and began firing a .45-caliber semi-automatic pistol on Wednesday afternoon. He then got into a vehicle and continued firing before entering another building and kept shooting. He was met by a female military police officer in a parking lot.
Lopez put his hands up but then reached under his jacket and pulled out his gun, military officials said. When the officer drew her gun, the suspect put his gun to his head and pulled the trigger.