Dozens of police officers using a helicopter, drones and sniffer dogs had combed rural wooded areas in the southern state looking for 32-year-old Joseph Couch.

On Sept 7, the former US military reservist legally bought an assault rifle and about 1,000 rounds of ammunition in the small town of London.

Later that day, he shot at cars driving along the I-75 highway, hitting 12 vehicles and wounding five people, before going on the run.

Authorities had offered a US$5,000 reward for any information leading them to Couch.

“I’m going to kill a lot of people. Well, try at least,” Couch is said to have written in a text message before the incident.

Couch also shared plans to take his own life after the shooting, according to a court document cited by local media.

Two state troopers and two civilians found an “unidentified body in deep brush” near the highway’s exit 49, Kentucky police commissioner Phillip Burnett Jr told reporters.

Troopers had targeted the area after seeing “vultures in the air,” he said.

Burnett said “articles associated with the body” had helped them conclude that they had found Couch’s remains.

“This is still an active investigation,” he said, but added that law enforcement was “very confident” the search for Couch had ended.

Gun violence is common in the US, a country where there are more firearms than people.

Despite polls showing Americans favour more gun restrictions, a powerful gun rights lobby, constitutional protections and a passionate culture of firearms ownership mean that gun control efforts are usually met with stiff political resistance.