A witness in the case against two accused accomplices of convicted killer Mark Hopkinson says Uinta County, Wyo., prosecutors are trying to prevent him from making parole.

Ron Hall, serving time in Utah for robbery, aggravated sexual assault and aggravated kidnapping, missed two appearances before the Utah Board of Pardons during a nearly 3-month-long stay in Evanston.Hall's attorney, Gil Athay, Salt Lake City, said the prisoner's extended detention in Evanston is "clearly punishment for not doing what (the prosecutors) wanted."

County officials, however, denied the charges.

If Hall's chances for parole and his family life have suffered because he has been held so long in Wyoming, his attorneys are responsible, said Deputy County Attorney Jim Anderson.

"All three defense attorneys said there was a possibility that Hall was going to be recalled to the witness stand," said Anderson, adding that he expects Hall will be returned to Utah shortly.

Hall, 50, testified during the recent preliminary hearing of his younger brother, Todd, and Hap Russell.

The two were charged with conspiracy to commit first-degree murder and aiding and abetting first-degree murder in the 1979 torture killing of Jeffrey Lynn Green.

Following the preliminary hearing they were bound over to state district court for trial.

A conviction for ordering Green's murder landed Hopkinson on death row at the Wyoming State Penitentiary.

Ron Hall charged that his stay in the Uinta County Jail is the result of his testimony at the preliminary hearing that the story he told a grand jury investigating Green's murder was concocted.

He also testified at the preliminary hearing that a Uinta County investigator had forced him to make the statements.

In a letter to the Casper Star-Tribune, Hall said special investigator Joel Miller threatened in 1982 to "press some old charges" if Hall did not provide false testimony to the grand jury. He wrote further that Miller promised to help him get out of prison in Utah if he cooperated.

"He told me he knew all the players but couldn't put them together," Hall wrote, "but with my false testimony he could clean this case up and get his job in Salt Lake County back.

"So he told me what to say, and I did," Hall said.

In his letter, Hall said that when he was brought to Evanston in February for the preliminary hearing, Uinta County Attorney Scott Smith told him he was "between a rock and a hard place" and would get five more years in the Utah prison if he changed his testimony.

On the other hand, Hall said, Smith promised that his cooperation would be rewarded by his placement in a federal witness program.

Smith declined to discuss the matter, but Anderson denied that any threats or promises were made in discussions with Hall before his Feb. 10 testimony at the preliminary hearing.

"We made the determination that no threats or promises would be made to him," Anderson said. "We did not want to purchase that testimony or have that appearance. When you do things like that, it puts a person's credibility into question."