WILLISTON (AP) - A man charged with killing a teenager in a convenience store robbery nearly 25 years ago made his first court appearance on the charge Friday, and a prosecutor said a plea agreement could be in the works.

William See Walker, of Fort Yates, already is serving a 30-year prison term for a 2005 conviction of molesting a 7-year-old girl.

He was charged in April with killing Gary Gerth, 18, of Bowman, in the Williston robbery on Dec. 4, 1982.

Authorities said Gerth, a Williston college student, was found shot to death after robbery at a convenience store where he worked as a clerk. They said about $140 was taken.

See Walker's appearance on the murder charge in Northwest District Court on Friday was through the state's video network. He sat beside his court-appointed attorney, Brenda Neubauer, at the State Penitentiary in Bismarck, while the rest of the participants were in Williston.

Gerth's parents, of Bowman, sat quietly in the Williston courtroom.

Williams County State's Attorney Nicole Foster said discussions have started about a plea agreement to avoid a trial.

"I think the potential of a plea agreement is good," she said.

Friday's hearing was to read the charges to See Walker. He did not enter a plea.

At Foster's request, Judge Gerald Rustad ordered See Walker to have no contact with the Gerth family.

Neubauer said she was surprised at the request.

"I have no objection to it; I feel it's unnecessary, and I'm not even sure why it was brought up," she said. "If the state feels it's necessary, go ahead and put it in place."

The charge against See Walker was announced by the attorney general's office after an investigation by its cold case unit.