Police reports describe concerns eight years ago that the gunman who killed seven and wounded 25 last month in West Texas might have been planning an attack.

Officers in Amarillo, Texas, went to the home of Seth Ator's mother in February 2011 after she told them he had refused to take his mental-health medication and had threatened to end his own life in a shootout with police,

They found a machete hidden in her son's bed and an underground shelter he had dug in the backyard. In a recording the mother shared with police, her son declared, "911 will bow down before me."

Police interpreted what they found as preparations for an attack and were so troubled that they recorded floor plans of the property and shared the information with the city's SWAT team, according to incident reports.

Officers believed Ator was volatile and might hurt somebody someday. Amarillo police spokesman Cpl. Jeb Hilton says that a documents request Sunday from The Associated Press about the February 2011 case has been forwarded to the agency's Open Records Department.

The police incident reports raise new questions about whether more could have been done to prevent Ator's shooting spree in the cities of Midland and Odessa, Texas. It's unclear how Ator, who once failed a background check for an attempted firearm purchase, acquired the AR-15-style rifle he used in the attack. Officers killed Ator outside a busy Odessa movie theater after the shooting rampage that lasted more than an hour.

"There seemed to be some indication of some planned standoff with police," one of the responding officers wrote in a report following the 2011 encounter.

Another officer stated in an incident report at the time that he believed Ator "will attempt to harm the police and the public."

After inspecting the home, officers transported Ator to a hospital and he was medicated and admitted to a mental health treatment facility, according to the report.

Police reports note that while in that facility Ator told security: "The police can't be everywhere." An officer stated: "I took this as a threat against the public."