Jeffrey MacDonald is serving three life terms for the 1970 murders that spawned the book and TV miniseries "Fatal Vision."
He is asking the 4th U.S. Circuit Court of Appeals to allow him to introduce new evidence, including DNA tests and sworn statements by two people who are now dead, supporting his claim of innocence.
MacDonald has always maintained that four drug-crazed hippies killed his family in their Fort Bragg, N.C., home.
His wife of nine years, Kathryn MacDonald, said after the hearing that she was encouraged by the appeals court's questioning.
A ruling is expected in a few weeks.
MacDonald's hopes of winning a new trial hinge largely on new DNA evidence and statements from two people that cast doubt on the testimony of Helena Stoeckley, the woman MacDonald claims was part of a band of drug-crazed hippies that killed his family in 1970.
A potential problem for MacDonald, 66, is that he has outlived the people whose sworn statements are crucial to his appeal - Stoeckley's mother, who said her daughter told her she was in the MacDonald home the night of the killings, and a former federal marshal who said he heard a prosecutor intimidate Stoeckley before the trial.
Stoeckley also is dead.
Prosecutors say in court papers that allowing those statements with no opportunity to hear live testimony would be improper. MacDonald, however, claims the statements are covered by a law that says evidence must "be viewed as a whole."
MacDonald argues the law also allows the DNA evidence, but the government wants the test results excluded because they were not among the items the court explicitly authorized for the appeal.
"Jeff is basically on a fifth appeal," said Kathryn MacDonald. "I can't think of any other case like this one, where 40 years after the fact it's being litigated as to whether the person is factually innocent or not."
MacDonald was an Army captain assigned to the Green Berets at Fort Bragg, N.C., when his wife Colette and daughters Kimberley, 5, and Kristen, 2, were slain on Feb. 17, 1970. The killings shocked a nation still reeling from the Charles Manson murders six months earlier.
Authorities received an early morning call from MacDonald reporting a stabbing, and when they arrived they found Colette and the children dead. MacDonald was wounded and lying next to his wife.
MacDonald told military police he slept on the sofa because Kristen, sleeping with her mother, had wet his side of the bed. He said he was awakened by their screams and was attacked by intruders - three men and a woman with long blond hair, a floppy hat and boots who carried a lighted candle and chanted "acid is groovy; kill the pigs."
However, investigators said physical evidence suggested MacDonald killed his family and then staged the scene. Investigators also argued that his injuries, which put him in a hospital for a week, were either self-inflicted or resulted from his fight with Colette.
Officers later remembered seeing a blonde in a floppy hat nearby but did not question her.
The Army began the equivalent of a grand jury proceeding, and after nearly three months the presiding officer declared the allegations against MacDonald "not true." MacDonald was honorably discharged and went to work as an emergency room doctor in Long Beach, Calif.
"48 Hours Mystery": Jeffrey MacDonald - A Time For Truth (7.21.07)
But federal prosecutors continued an investigation that led to his 1979 trial. They theorized that a club-wielding MacDonald fought with his wife over the wet bed, accidentally killed Kimberley when she tried to intervene and then killed his wife and Kristen. Character witnesses, however, described the Princeton-educated MacDonald as a loving father and husband who had never shown violent tendencies.
The key defense witness was expected to be Stoeckley, who had told conflicting stories about whether she was in the MacDonald home. However, she testified she could not remember the period when the slayings occurred.
MacDonald was convicted and sentenced to three consecutive life terms. The 4th Circuit tossed the convictions on speedy trial grounds, and he returned to work at the California hospital. But within two years, the U.S. Supreme Court reinstated the convictions, and MacDonald returned to prison.
Two years later, "Fatal Vision" was published. MacDonald had expected the book to portray him as innocent, but author Joe McGinniss instead became convinced MacDonald was guilty. "Fatal Vision" was made into a highly-rated TV miniseries in 1984.
In 2006, the appeals court ruled that MacDonald could seek a new trial in federal district court based on retired Deputy U.S. Marshal Jim Britt's claim that he heard prosecutor James Blackburn coerce Stoeckley into lying. Blackburn told Stoeckley she'd be charged with the crimes if she admitted to being in the MacDonald home the night of the killings, Britt said.
Britt died in 2008, and Senior U.S. District Judge James C. Fox rejected MacDonald's bid for a new trial two weeks later. MacDonald's lawyers appealed to the 4th Circuit, citing errors during the trial and "startling new evidence" to prove his innocence.
In addition to the statements by Stoeckley's mother and Britt, MacDonald is citing the long-awaiting results of DNA testing of three hairs, including one found under Kristen's fingernail. The tests excluded MacDonald or anyone in his household - evidence that MacDonald claims points to intruders.
Prosecutors say the test results also eliminate Stoeckley and her boyfriend, Greg Mitchell, who also had told conflicting stories about whether he was involved in the slayings. Mitchell died in 1982.
MacDonald will remain in the federal prison in Cumberland, Md., for Tuesday's hearing, but his wife and some of his friends plan to be in the courtroom.
"Each time something comes up and he has another hearing, you think somebody's going to do the right thing," said Ray Shea of Arlington, a longtime friend whose brother worked with MacDonald at the California hospital.
Kathryn MacDonald said that if her husband is ever exonerated and freed, he would like to get his medical license back.
"All he wants to do is get a barbecue and have friends over and make shrimp and beef kabobs on the grill, watch football on TV and feel grass under his feet," she said.