He appeared to be disturbed that day for a multitude of reasons. He had been fired that morning from his trucking job for an oil-field services company. He called 911 afterward, and later made a ranting phone call to the F.B.I.’s national tip line, a phone number he had called several times in the past. During the shooting spree, he called 911 and admitted to dispatchers that he was the killer.
The authorities have said the firing that morning was only one of the issues that had upset him. “When he showed up to work, he was already enraged,” Christopher H. Combs, the special agent in charge of the F.B.I.’s San Antonio office, said this week.
The authorities said that the gunman had previously failed a background check to buy a gun in Texas, and that he did not go through a background check to buy the AR-15-style rifle he used in the attack. ABC News reported on Tuesday that he acquired the weapon through a private-sale loophole and was barred by law from buying or possessing a firearm because he was diagnosed as being mentally ill. A spokeswoman with the federal Bureau of Alcohol, Tobacco, Firearms and Explosives declined to comment, saying only that the agency “does not plan to release any additional details” as it continues to investigate.
After a 2001 misdemeanor arrest in the Waco area in McLennan County, where he grew up, he was considered a suicide risk by the county sheriff’s office and placed on a 15-minute suicide watch during his incarceration, according to sheriff’s records.
Local, state and federal officials have not established a clear motive in the Odessa attack. One friend of the gunman’s family said the shooter had a long history of mental problems and making racist comments.
Asked whether investigators believed that the gunman targeted Hispanics, a spokesman for the Odessa police said it remained under investigation.
Several Hispanics were among the victims in Saturday’s attack, violence that unfolded just weeks after a man killed 22 people in an anti-Hispanic attack at a Walmart in El Paso. Federal officials in El Paso said they were treating that attack as domestic terrorism because it was designed to intimidate a civilian population.