FRANKFORT, Ky. — Kentucky State Police said the State Medical Examiner performed an autopsy on the body found Sept. 18 in Laurel County, which is believed to be that of 32-year-old Joseph Couch, the suspect of the Sept. 7 Interstate 75 mass shooting. 

William Ralston, chief medical examiner, said the office performed a soft tissue DNA test, but the results were inconclusive. The next step is to conduct testing on DNA extracted from bone, KSP said, which will begin Sept. 20. Results could take 24 to 48 hours.

Ralston added the autopsy revealed the cause of death "to be a wound consistent with a self-inflicted gunshot to the head," and authorities are also performing a toxicology test to determine if any drugs were present.

During a Sept. 18 news conference, KSP Commissioner Phillip Burnett Jr. said troopers found evidence that afternoon on the body associated with Couch. KSP credited married couple Fred and Sheila McCoy with helping authorities finding the body, who had spent several days looking for Couch, while KSP and other agencies conducted a multi-day manhunt that involved searching more than 28,000 acres of the Daniel Boone National Forest. Laurel County Sheriff John Root said the McCoys will receive $15,000 from Laurel County Crime Stoppers, in addition to $10,000 from a private donor, adding Couch's family worked with authorities throughout the investigation.

Couch is accused of shooting 12 vehicles and wounding five people. He fired 20 to 30 rounds in the attack and is charged with five counts of attempted murder and five counts of assault.