May 14, 2010 -- Forty years have passed since one of the most infamous and grisliest crimes in American history.
Jeffrey MacDonald's young wife, Colette, and their daughters were brutally bludgeoned and stabbed to death in their home in Fort Bragg, N.C., in what seemed like a pointless and murderous fury. Then 26-year-old MacDonald was left alive.
MacDonald, a Green Beret, a graduate of Princeton University, and a respected doctor, told investigators that he had been sleeping on the couch when he heard his wife and children calling for help and awoke to find three male intruders and a mysterious woman in a floppy hat and boots chanting, "acid is groovy, kill the pigs."
He said was attacked, defended himself, blacked out and awoke to the horror of his blood-covered wife and children.
The murders came just months after Charles Manson's drug-addled "family" slaughtered actress Sharon Tate and others in California. Just as Manson's family wrote "Helter Skelter" and "pig" in their victims' blood, "pig" was written in blood in the MacDonald home.
But to Army investigators and then later to federal prosecutors, it was all wrong. The crime scene seemed staged and hardly anything was damaged after a supposedly ferocious, Manson-style home invasion.
Most damningly, the blood and fiber evidence told a tale that convinced prosecutors and ultimately 12 jurors that MacDonald had made up his story and had slaughtered his own family.
The savage killings became known as the "Fatal Vision" case, after a best-selling book and TV miniseries. After an explosive trial in 1979, MacDonald was found guilty and sentenced the three life sentences for the murders.
But MacDonald never accepted the guilty verdicts. Now 66, he is an inmate in a federal prison in Maryland and his case is back in court, before the Fourth Circuit Court of Appeals in Richmond, Va.
MacDonald's wife of nine years, Kathryn MacDonald, has hope.
"I know this case backwards and forwards and I know this man that I love. But, I knew it before I loved him," said Kathryn MacDonald, who married Jeffrey MacDonald in federal prison in 2002, just five years after she wrote to him about his case. "I just want him to come home now. He deserves to be home."
Kathy MacDonald, who runs a children's theater program outside Baltimore, has an encyclopedic knowledge of the facts and law of the MacDonald murder case. She told "Nightline" they've put their entire life savings into the appeals.
"I don't think that our system is set up for the average person, citizen like myself. I'm not a lawyer, I'm not a doctor, and you go through everything you have. And Jeff went through everything he had," she said. "I don't think that there's any price you can put on justice, don't get me wrong."
New Questions About MacDonald Case
MacDonald's lawyers argue he deserves a new trial based primarily on statements made by people tied to the case that had not previously been heard and new DNA findings.
Two key pieces of evidence that the defense said they would like to have examined in the appeal relate to Helena Stoeckley, a self confessed drug addict, who came forward after the murders and claimed to investigators she may have been involved and was the woman MacDonald had seen in his house.
Stoeckley's story changed over the years and when she was called to testify at MacDonald's trial, she denied she had any memory of the four-hour period during which the murders took place.
Stoeckley died in 1983. But in 2006, Jimmy Britt, a former U.S. deputy marshal at the trial, who died in 2008, swore in an affidavit that he heard a prosecutor threaten Stoeckley before she testified. MacDonald's lawyer said that's crucial information.
"It is definitely serious prosecutorial misconduct if, in fact, the prosecutor threatened a defense witness," said Hart Miles, one of MacDonald's lawyers.
Miles also pointed to a 2007 affidavit from Stoeckley's mother who said that shortly before Helena died, she told her mother she was there in the house the night of the murders.
MacDonald's lawyers assert that new DNA evidence from the crime scene, which was tested in 2006, will show that MacDonald is innocent, after all.
"There was a hair found under the fingernail of Kristen MacDonald, Jeffrey MacDonald's youngest daughter, and DNA testing showed that was an unsourced hair, that it did not match Jeffrey MacDonald or anybody else in his family," Miles said. "Our position is that it corroborates the story that he's told from the very beginning, that there were intruders in that house."
The government's theory was that MacDonald had "got into a fight with his pregnant wife because his youngest daughter, Kristen, had wet the bed; that he picked up a club to strike his wife and accidentally struck and killed his daughter, Kimberley, who was trying to intervene; and that then, in order to cover up his accidental misdeed, killed his wife and then mutilated and killed his youngest daughter and tried to make it look like a cult slaying," court papers said.
MacDonald's blood, along with fibers from his torn pajamas, were found on and under the victims' bodies. No DNA evidence, fingerprints or fibers from Helena Stoeckley were found anywhere in the house.
Prosecutors have never wavered.
"I don't believe Jeffrey MacDonald will ever admit to killing his family," said Jim Blackburn, the prosecutor during the trial. "He is not going to live forever and there is going to come a time, if you believe in this sort of thing, when he's going to be able to see Colette and Kimberley and Kristen again, and the question he's going to have to answer to them and the question I would ask of Jeffrey MacDonald is: Was it all worth it?"
Kathryn MacDonald believes the prosecution's case is crumbling.
"If the only way to get a conviction was to hide anything that didn't fit with the prosecution's theory, they did a good job at the time. But now it's all unraveling. Please, please, a neutral party, look at this evidence as a whole. And that is the law, look at it as a whole. And our government doesn't want that," she said. "I hate all this, I can't wait for it all to be gone and life to start anew."
A ruling on whether or not MacDonald will get an appeal is expected in the coming weeks.