Wilmington (ABC News) - Lawyers for convicted "Fatal Vision" killer Jeffrey MacDonald presented new evidence to a court [Monday], including a statement by a former U.S. marshal who claims a witness initially said she was at the MacDonald house the night of the murder, but later changed her story.
MacDonald, who was convicted of killing his wife and daughters 33 years ago, could be granted a new trial if a judge deems new evidence to be sufficient.
The evidentiary hearing for the 68-year-old former Green Beret doctor, who is serving three life sentences, began [Monday] in a Wilmington, N.C. federal courtroom and is expected to last two weeks.
During his time in prison, MacDonald remarried. His wife Kathryn was seen in the courtroom today, acting as a supportive presence and blowing her husband kisses.
The decision for a new trial hinges on DNA evidence and a sworn affidavit from a now-deceased U.S. Marshal who came forward in 2005 with a "moral burden" he said he kept for decades.
In 1979, U.S. Marshal James Britt had been tasked with driving Helena Stoeckley, who was considered a witness, from the county jail in Greenville, S.C. to Raleigh, N.C. for questioning before MacDonald's trial.
During the nearly 300-mile trip, "without any prompting from me whatsoever, Ms. Stoeckley brought up the matter of the trial of MacDonald," Britt, who passed a polygraph test, wrote in a sworn affidavit dated Nov. 3, 2005.
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Stoeckley told Britt and an administrative assistant who accompanied him on the trip, that she had been in the MacDonald house the night of the murders to acquire drugs and provided details about the house, including the presence of a hobby horse, according to the affidavit.
Britt said he heard Stoeckley confess a second time at the court house, this time to U.S. Attorney James Blackburn.
"If you testify before the jury as to what you have told me or said to me in this office, I will indict you for murder," Blackburn told Stoeckley, according to Britt's affidavit.
MacDonald's defense attorneys contend this moment, recalled decades later by Britt, caused Stoeckley to change her story on the stand. Stoeckley is also now deceased.
What Britt said he heard weighed on him for decades.
DNA evidence that was not available at the time of MacDonald's trial may also be key to exonerating him. Three unsourced hairs were found at the crime scene and blood was found under the fingernail of one of the victims, defense attorneys said.
MacDonald has long maintained his innocence, insisting that on Feb. 17, 1970, a group of drug-fueled hippies broke into his home, beating and stabbing his wife Colette, and their two daughters, Kimberley, 5, and Kristen, 2. The word "Pig" was sprawled in blood on the headboard of MacDonald's master bedroom.
The gruesome murders, which came months after details of the Manson Family murders were revealed, captivated the nation and eventually spawned a bestselling book, "Fatal Vision," and a 1984 television mini-series.
Freddy Kassab, MacDonald's father-in-law, initially stood by him following the murders, however over time his confidence in MacDonald's story faded. He pushed for charges to be brought against his son-in-law.
MacDonald was convicted in 1979, nine years after the slayings.
In a letter provided to the Associated Press from 2000, MacDonald wrote to his new wife, Kathryn: "It would be a dishonor to their memory to compromise the truth and 'admit' to something I didn't do — no matter how long it takes."
If he is not granted a new trial, MacDonald's next opportunity for freedom will be in 2020 when he becomes eligible for parole.