ST. JOHNS COUNTY, Fla. -

A man who pleaded no contest to second-degree murder for a 2007 killing was sentenced Wednesday to life in prison.

Prosecutors said Phillip Pomper killed 31-year-old Clark McWhorter (pictured, below) in what they called a random killing.

The sentence was handed down after McWhorter's mother gave a victim impact statement. She traveled to St. Johns County from Texas to get justice for her son.

On Jan. 28, 2007, McWhorter's body was found in the roadway on Coastal Highway in Guana State Park. An autopsy revealed he died from a single gunshot wound, deputies said. Investigators initially thought he had been run over by a car and killed.

After receiving tips from witnesses, detectives said they ascertained that Pomper, of Jacksonville, had specific knowledge of the killing.

Clark McWhorter

With the assistance of the Jacksonville Sheriff's Office and the U.S. Marshals Service, detectives with the St. Johns County Sheriff's Office were able to locate Pomper.

During an interview, detectives said, Pomper admitted to his involvement in McWhorter's death. Pomper told investigators he did not know McWhorter (pictured right).

The information he provided led detectives to believe the killing was completely random and unprovoked, detectives said.

Investigators said McWhorter was walking alongside the road and it was raining that night. They said Pomper pulled up alongside him and asked if he needed a ride. Investigators said McWhorter got in the car, and that's when detectives said Pomper shot him.

Pomper was arrested in Jacksonville on two counts of sexual assault stemming from a different case. Investigators said he molested a young girl staying in his house.