The 36-year-old man who went on a shooting rampage Saturday in the Odessa-Midland area of Texas was fired from his job at a trucking company hours before he indiscriminately opened fire on people.

The shooting began with a routine traffic stop after he failed to use a turn signal. The man then opened fire on police and led officials on a high-speed chase during which he fired on people, killing seven and injuring 22 others.

While the gunman in the latest attack had a criminal record, there were no open warrants for his arrest when the police tried to pull him over Saturday afternoon, Chief Gerke said. Mr. Ator had been arrested in August 2001 in McLennan County near Waco on misdemeanor charges of criminal trespass and evading arrest, according to state records. “This is a different type of active shooter that we were involved with, because he was mobile, and that creates some very special type of issues,” Chief Gerke said. The gunman sped away from the state troopers who had tried to pull him over, and then hijacked a United States Postal Service van, killed its driver, and began firing at people randomly as he drove. In cellphone video from witnesses that captured the final moments of the shooting spree, the postal van speeds into view and slams into a police cruiser outside the movie theater in Odessa. A burst of gunfire followed as officers who had been chasing the van rushed out and shot the gunman, who appeared to still be inside the van. (NYT)

Despite the revelation that he had been terminated from his job hours before, authorities said a clear motivation had yet to be determined.

“There are no definitive answers as to motive or reasons at this point, but we are fairly certain that the subject did act alone,” Odessa Police Chief Michael Gerke said at a news conference.