Shootings on Arizona’s I-10 Put Drivers on Alert

Serial sniper? 4 vehicles shot along Phoenix interstate 1:48

Someone is shooting at cars along an Arizona highway.

Officials are investigating four separate shootings over three days along I-10. It was not immediately clear if the incidents were related.

Multiple rounds were fired in all of the incidents, according to NBC station KPNX. Investigators believe the shooter was also in a vehicle traveling on I-10, KPNX reported.

The shooting occurred on Saturday just after 11 a.m. local time when a sport utility vehicle was fired upon and struck, according to a statement from the Arizona Department of Public Safety. A teen girl riding in the passenger seat was treated on the scene for a cut to her right ear.

Minutes later, according to officials, a bus traveling in the opposite direction was hit by a bullet. There were no injuries.

Bus driver Robert McDonald told KPNX that he heard a loud bang while driving but assumed he'd hit something and didn't think much of it. When he stopped for a Coke, McDonald saw a bullet hole on the front of his tour bus.

Shootings Along I-10 in Arizona have Authorities on Alert 1:06

"I almost fainted," he said. "The wind got knocked out of me."

The third shooting was later that night. The department of public safety said a driver told detectives she heard a "loud banging sound" but did not check her vehicle until the following day, at which point she "noticed bullet holes" on the passenger side.

Early Monday, a bullet hit a work truck en route to a work site.