The woman got out of her vehicle, and Riggleman ran her over, Merrill said. The woman was taken to a nearby hospital; her condition is not known.
Riggleman continued south on Interstate 79 until he stopped at an Exxon gas station in Amma, Roane County, just before 8 p.m.
According to witnesses, he tried to take a car owned by station employee Donnie Nichols. When Nichols tried to stop him, Riggleman shot him in the neck with a .30-30 deer rifle.
A spokeswoman at CAMC General Hospital said Nichols was in the hospital's intensive care unit Tuesday morning, but witnesses said he was alert and talking immediately after the shooting. A woman who came upon the scene immediately after the shooting and called 911 said Nichols asked her to call his wife.
After the shooting, Riggleman's Jeep sped off. It was next seen by sheriff's deputies in Lewis County, Ky., who took up the chase.
Lewis County sheriff's deputies chased Riggleman near Spy Run Cemetery Road before pulling him over. When deputies approached the vehicle, Riggleman shot himself with a .30-30 rifle, Merrill said.
Police found two rifles, a .22 caliber pistol and several rounds of ammunition in the Jeep, he said.
Police believe Riggleman's killing spree would have continued into Tennessee if police had not pulled him over in Kentucky.
Among the updates on Riggleman's public Facebook page hours before the shooting, one said, "why wouldn't they let me join the military? I'm fully capable, and there was no career for me!"
On Thursday he posted three updates, "Even a mule tries to kicks its opressor, come on human beings stand up!" and "I mate for life, not like a penguin though. I mate for life like a praying mantis." and "We're not promised tomorrow..."
He lists one of his favorite quotations as, "I ain't goin' out without a fight. I'm with whatever. it WILL be YOUR LIFE before MY LIFE."
A message exchange on Riggleman's Facebook wall indicates that he has one son.