Schools in several Kentucky counties remained closed on Monday as the manhunt for a man suspected of shooting at vehicles along a major highway, injuring five people, continued for a third day.

Police have named 32-year-old Joseph A. Couch as a suspect in Saturday night’s shooting.

Authorities believe the attacker is in a remote, rugged area about 9 miles from the city of London in southeastern Kentucky.

The Laurel County Sheriff’s Office said it seized a silver Honda SUV and an AR-style rifle believed to have been used in the attack, although the suspect may have other firearms.

Police also found a phone they believed belonged to Couch, but with the battery removed.

Hours before the shooting, Couch legally purchased the rifle and about 1,000 rounds of ammunition, police said.

The shooting began at around 5:30 p.m. local time (21:30 GMT) on Saturday. Police initially said nine vehicles were hit by gunfire on Interstate 75, a busy north-south route, but later revised that figure to as many as 12 cars hit.

The shots were fired from a ledge on a cliff above the highway.

Five people were injured, some of them with “very serious” injuries, officials said. One person was shot in the face.

All were in stable condition on Sunday and were expected to survive.

Randall Weddle, the mayor of London, Kentucky, said some local businesses and churches remained closed Sunday while the manhunt continued.

Authorities urged residents to remain vigilant while the suspect remains at large.

“You need to lock your doors,” Kentucky State Police spokesman Scottie Pennington said Sunday. “If you have security cameras, make sure you keep an eye on them at all times. Maybe leave your porch light on, too.”

As a precautionary measure, schools in Laurel County, where London is located, and several neighboring counties were closed on Monday.

Officials said the woods in the area are very dense and the search is moving slowly. The hunt was called off after dark Sunday night, but officers remained in a wooded area near Exit 49 on I-75 to detain the suspect.

“This is probably one of the most remote exits on I-75,” Deputy Gilbert Acciardo of the Lauren County Sheriff’s Office told reporters during a press conference. “It’s a big job.”

Mr Acciardo described the scene as a “madhouse” when first responders arrived.

“People on the side of the road, hazard lights on, bullet holes, windows shot out,” he said. “Can you imagine? Just chaos.”

Police said they had not yet determined a motive for the shooting, but described it as a random and not targeted attack and said Couch had previously served in the National Guard.

The town of London has about 8,000 inhabitants and is located near the Daniel Boone National Forest.

Christina DiNoto, who was traveling with a friend on I-75 at the time of the shooting, told CNN that it was “like a rock went through my rear window” and injured her ear.

“We looked at each other and thought, ‘Was that a shot?’ And then we said, ‘No, that wasn’t a shot.'”

She said they didn’t find out there had been a shooting until an hour and a half later.

Kentucky Governor Andy Beshear wrote on social media that the area should be avoided and asked the public to “pray for everyone involved.”