The gunman who killed seven people in West Texas got his AR-style rifle through a private sale, after failing a background check in 2014 over a “mental health issue,” an official told The Associated Press Tuesday.

The official, who talked to The Associated Press on condition of anonymity, said Ator was able to skirt the background check process by obtaining the gun through the private sale.

Texas Gov. Greg Abbott tweeted Monday that Seth Aaron Ator, 36, failed a previous gun background check and didn't go through one for the weapon he used in Odessa, but didn't elaborate on when Ator failed the background check or the reasons why.

Ator had a criminal history in McLennan County.

Court records obtained by KWTX show an arrest in August 2001 on charges of criminal trespass and evading arrest.

According to online records, McLennan County deputies arrested Ator on Aug. 3, 2001 in connection with a criminal trespass incident on Aug 1, 2001 and for evading arrest the next day.

He pleaded guilty to the misdemeanor charges in McLennan County Court at Law and was sentenced on Feb. 28, 2002 to 24 months deferred adjudication probation, online records show.

The offenses would not have prevented Ator from purchasing a weapon.

Ator attended Lorena schools from January 1995 to November 2000, but did not graduate, the Lorena ISD said in a statement Monday, correcting earlier reports that Ator was a 2001 Lorena High School graduate.

During that time frame, Ator moved several times between Canyon ISD in Amarillo and Lorena ISD,” the district said.

“Lorena ISD records show Ator withdrew from Lorena High School in November of 2000 to enroll in a GED program,” the district said.

“Our hearts and prayers go out to the victims and their families of the tragedy in Odessa.

Lorena resident Niki Lehmann was a year ahead of him and says they hung out in different circles but she doesn't remember him as a bad kid.

"He was a nice kid, I know he played football," said Lehmann. "I was surprised, I was really surprised, yeah, shocked that he would do something like that, that it would have a connection with anybody in Lorena."

Department of Public Safety troopers attempted to stop Ator on Saturday for a traffic violation in Odessa, when he opened fire.

They say he went on a 10-mile shooting rampage, hijacking a mail carrier truck and firing at random as he drove in the area of Odessa and Midland.

The Odessa police chief said during a news conference Sunday the gunman used an "AR-type weapon" during the shooting rampage.

Police shot and killed Ator outside a movie theater in Odessa.

Investigators said Ator has no connection to terrorist organizations and no motive for the shootings has been established.

The first shooting was reported at approximately Saturday afternoon when a state police officer attempted to pull over a vehicle heading west on Interstate 20 near mile marker 131.

State police said Ator was stopped for failing to signal a left turn while driving.

Prior to the vehicle coming to a complete stop, the Ator allegedly pointed a rifle toward the rear window of his car and fired several rounds in the direction of the DPS patrol unit, police said.

The patrol unit was occupied by two troopers. A trooper struck by a round was hospitalized. He is listed in serious, but stable condition.

The driver of the vehicle then led authorities on a chase in the Midland-Odessa area. He carjacked a United States Postal Service vehicle during the pursuit, allegedly killing the mail carrier in the process.

Ator allegedly continued the shooting rampage while driving the stolen USPS vehicle.

He was eventually stopped outside the movie theater where he was killed.

The seven people allegedly killed in the rampage range in age from 15 to 57.

The slain mail carrier has been identified as Mary Granados.

At the time of the shooting rampage, the Texas Department of Public Safety was urging the public to avoid I-20 in Odessa, Midland and Big Spring as authorities "searched for two active shooters."

Texas Attorney General Ken Paxton expressed his horror on Twitter. "I am horrified to see such a senseless act terrorize the fine people of the Permian Basin," Paxton said, "Thank you to the courageous local and state first responders who worked quickly to stop this evil attack."

(Rissa Shaw contributed to this story)