A Casper man pleaded guilty to stealing a man's car supposedly at gunpoint last year during a hearing in Natrona County District Court on Friday.

Jason Christopher Billings, who was 35 when arrested, entered his change of plea to one count of robbery before District Court Judge Thomas Sullins.

In exchange for his plea, Assistant District Attorney Dan Itzen proposed, and Billings' attorney Todd Infanger agreed, to a suspended four- to six-year prison sentence if he successfully completes a three-year term of probation.

Sullins agreed to the terms of the plea agreement.

Billings earlier pleaded not guilty and not guilty by reason of mental deficiency.

If the case had gone to trial, and Billings was convicted, he could have faced a prison sentence of up to 10 years.

Billings has been free on bond.

The case began the evening of May 30 when a man reported his car had been stolen, according to court documents.

Meanwhile, the Wyoming Behavioral Institute notified police a patient had escaped.

The robbery victim told police he arrived at his home on East 15th Street, and after getting out of his car was "rushed" by Billings.

Billings grabbed the man by the shirt and demanded the car keys. The victim refused.

Billings reportedly said he had already killed two people, and he would make the victim his third.

The victim told police he saw what he believed to be a gun in Billings' hand, so he gave him his keys.

Court documents say Billings, who was identified as the WBI escapee, got in the car and drove away.

Later that evening, an Evansville police officer found the stolen car at Eastgate Travel Plaza on Hat Six Road. Law enforcement officers responded, established a perimeter, called the travel plaza and the staff confirmed Billings was in the store.

Court documents say officers went inside and arrested Billings, who was "cooperative and courteous," without incident.

In an interview with a detective, Billings said he was involuntarily committed to WBI the day before, and escaped after multiple attempts.

Billings said he ran down a hill where he saw the victim pull into his driveway, waited for him to get out of his car, ran to him and demanded his keys.

The man refused, so Billings said he grabbed him by the shirt and said, "I just need your car, I don't want to hurt you."

The victim gave the keys in Billings, who said he drove to the travel plaza to get fuel.

But Billings accidentally locked the keys inside the car, tried to get another ride and police found him.

He reportedly said his plan had been to go "on the run," cutting all ties with family and loved ones.

During the police interview, Billings asked for a pen and paper, then started writing an apology letter to everyone involved in the incident.