Nelson said Tuesday that part of the petition was based on testimony at trial that Harshman threatened another man who was involved with his former wife.
Harshman's petition claimed his trial attorney, David S. Keller, failed to present "exculpatory evidence contained on tape recordings surreptitiously made by the Pennsylvania State Police" of conversations he had with his daughter and Snyder's widow, Joan Snyder Hall.
"When they did those wiretaps ... Harshman did not admit that he did it," Nelson said of the recordings, which the prosecution did not use. Otherwise, the tapes were of little value as evidence to either side, he said.
The petition also stated Keller failed to object to the introduction of "hearsay testimony that Mr. Harshman had threatened to kill Melvin Snyder," and should have asked for a mistrial at another point during the trial.
Without a body, murder weapon or eyewitnesses, the case against Harshman was based largely upon his motive and two shell casings found 14 years apart at different locations.
Harshman's wife and Snyder began an affair in May 1984. When she told him in June that she and Snyder were running away to Montana, Harshman ran his pickup into Snyder's pickup and fired two shots at him, according to trial testimony.
Harshman was placed on probation for the incident, according to court records.
When Snyder disappeared the next year, police found a spent .25-caliber shell casing in his barn, according to trial testimony. On July 15, 1999, police found a similar shell casing at Harshman's former property in Antrim Township, Pa., and a ballistics expert testified at trial that both were fired from the same gun.
In October 1999, a county investigating grand jury issued a presentment recommending Harshman be charged with criminal homicide, according to court records. In April 2000, Harshman and Joan Snyder Hall both were charged with criminal homicide and criminal conspiracy in Snyder's disappearance.
Charges against Joan Snyder Hall later were dismissed, according to court records.
Harshman has been serving his life sentence at Rockview State Prison in Bellefonte, Pa., since his July 14, 2001, conviction, Nelson said.
Several calls to Harshman's attorneys in Harrisburg, Pa., were not returned.