ODESSA, Texas — Police say they are not sure why a man with a misdemeanor on his record and no warrant for his arrest erupted in a spate of violence after a routine traffic stop in West Texas, killing seven, including a man slain outside his parents’ home and a teenager fatally shot as she left a car dealership with her family.

Authorities said Seth Aaron Ator, 36, also injured 22 people Saturday before officers killed him outside a busy movie theater in Odessa.

Online court records show Ator was arrested in 2001 for a misdemeanor offense that would not have prevented him from legally purchasing firearms in Texas, although authorities have not said where Ator got the “AR style” weapon he used.

Authorities said those killed were between 15 and 57 years old but did not immediately provide a list of names. Family and employers, however, said that among the dead were Edwin Peregrino, 25, who ran out of his parents’ home to see what the commotion was; mail carrier Mary Granados, 29, slain in her U.S. Postal Service truck; and 15-year-old high school student Leilah Hernandez, who was walking out of an auto dealership.

Hundreds of people gathered at a local university in the Permian Basin region known for its oil industry Sunday evening for a prayer vigil to console each other and grieve the loss of life.

“We’re out here in the middle of nowhere,” Midland Mayor Jerry Morales told the crowd. “All we’ve talked about is oil forever. And then this happens.”

Odessa Police Chief Michael Gerke said there were still no answers pointing to a motive for the chaotic attacks, which began when Texas state troopers tried pulling over a gold car on Interstate 20 for failing to signal a left turn.

Before the vehicle came to a complete stop, the driver “pointed a rifle toward the rear window of his car and fired several shots” toward the patrol car stopping him, according to Texas Department of Public Safety spokeswoman Katherine Cesinger. The gunshots struck a trooper, Cesinger said, after which the gunman fled and continued shooting. He fired at random as he drove in the area of Odessa and Midland, two cities more than 300 miles (482 kilometers) west of Dallas.

Police used a marked SUV to ram the mail truck outside the Cinergy Movie Theater in Odessa, disabling the vehicle. The gunman then fired at police, wounding two officers before he was killed.

“Local law enforcement and state troopers pursued him and stopped him from possibly going into a crowded movie theater and having another event of mass violence,” FBI special agent Christopher Combs said.

Police said Ator’s arrest in 2001 was in the county where Waco is located, hundreds of miles east of Odessa. Online court records show he was charged then with misdemeanor criminal trespass and evading arrest. He entered guilty pleas in a deferred prosecution agreement where the charge was waived after he served 24 months of probation, according to records.