North Dakota ? A man already serving a 30-year prison sentence for molesting a child has been charged in the shooting death of a teenage clerk during a convenience-store robbery nearly 25 years ago, authorities said Friday.

William See Walker, 48, of Fort Yates, has been transferred to North Dakota’s state penitentiary from a federal prison in Colorado to face the murder charge, state Attorney General Wayne Stenehjem said.

Stenehjem would release few details of the arrest, saying he did not want to compromise the court case.

Gary Gerth, 18, of Bowman, was found dead on Dec. 4, 1982, inside the Mon-Dak convenience store in Williston. Police estimated about $140 was taken from the store.

Gerth was a college student who worked part-time at the store in rural northwestern North Dakota.

Brenda Neubauer, an attorney representing See Walker, said she had no comment Friday. See Walker was convicted in 2005 of molesting a 7-year-old girl.