CHAMBERSBURG, Pa. — A man sentenced to life in prison for a West Virginia slaying now faces charges in a killing on a Pennsylvania interstate that state police say appeared to be a case of mistaken identity.

Thirty-nine-year-old John Wayne Strawser Jr., of Terra Alta, West Virginia, was sentenced to life in prison last week in the April 2015 shooting death of Amy Lou Buckingham in Preston, West Virginia.

In Pennsylvania, he is accused of chasing down and killing 28-year-old Timothy Davison, an apparent stranger from Poland, Maine, along Interstate 81 in January 2014.

Franklin County District Attorney Matt Fogal said Pennsylvania authorities have begun extradition proceedings to bring Strawser back to the state for trial. Fogal said he hopes the process will take no longer than a month.

Davison was driving home after visiting family members in Florida when the driver of a pickup truck started firing at him as the two vehicles crossed from Maryland into Pennsylvania before dawn, authorities say in court documents. The truck then rammed Davison’s sport utility vehicle, forcing it onto a snow-covered median, the documents say.

The driver circled back minutes later, as Davison was talking on the phone to a state police dispatcher, and shot Davison several times in the head, leg and foot before fleeing, authorities say. Davison died shortly afterward at York Hospital.

A couple who described themselves as former friends of Strawser came forward after he was charged in the West Virginia slaying, saying they had been traveling north on I-81 around the same time and in the same vicinity of the shooting.

They said Strawser had threatened them in cellphone calls and text messages and they believed he was looking for them and mistook Davison’s silver Mitsubishi Montero for their silver Honda Pilot.