Judge to hear new testimony in slaying of Green Beret doctor's family

(CNN) -- One of the most sensational and infamous murder cases in modern U.S. history is returning to a courtroom this week.

A federal judge in Wilmington, North Carolina, will begin hearing testimony Monday morning on whether Jeffrey MacDonald, the former Green Beret doctor convicted of killing his family, should get a new trial.

MacDonald, 68, is expected to be present at the proceedings. He has long said that a group of hippies beat and stabbed to death his wife and two young daughters in their Fort Bragg, North Carolina, home on February 17, 1970.

MacDonald told investigators that he was at home, sleeping on a couch, when he heard screaming. He awoke to find three men and one woman, whom he described as having blond hair and wearing a floppy hat. They chanted "kill the pigs" and "acid's groovy" before attacking him, MacDonald said. He suffered two stab wounds and a collapsed lung.

A military inquiry into the murders recommended that MacDonald not be court-martialed, but a federal jury found him guilty in 1979. He was sentenced to life in prison and has been behind bars since 1982.

The U.S. Court of Appeals for the Fourth Circuit last year ruled that MacDonald is entitled to an evidentiary hearing. He and his attorneys will argue that new DNA tests show that hair samples found underneath the fingernail of one of the victims did not come from a member of the MacDonald family and presumably were from one of the killers.

The defense team will also try to prove that the prosecutor in the criminal trial threatened Helena Stoeckley, a witness who had earlier confessed to being in the MacDonald home the night of the murders.

On the stand, she said she was not present and had no involvement in the killings. The defense insists the prosecutor, James Blackburn, pressured Stoeckley to alter her testimony. Stoeckley, who had a long history of drug and alcohol abuse, died in 1983.

Blackburn would not comment on the charge, citing Monday's hearing.

"I was the prosecutor in the case, and I did that job to the best of my ability," Blackburn told CNN. "I did it in great reliance of the evidence the government had, and we presented an honorable case and it was straightforward and it was based on good and competent evidence. And I agree with the jury's verdict."

The MacDonald saga has captivated the public's attention for decades. It also became the focus of the controversial and popular book "Fatal Vision" by Joe McGinniss. On television, millions watched the miniseries about the case and a memorable "60 Minutes" interview with MacDonald.

This month, Academy Award-winning documentary filmmaker Errol Morris spoke to CNN about "A Wilderness of Error: The Trials of Jeffrey MacDonald," his new book on the subject.

"We've been sold a bill of goods about this case," Morris said. "It's as phony as a three-dollar bill."

"There are many things about this case that rub me the wrong way, but principal among them was how the jury was asked to make decisions about his guilt or innocence with incomplete evidence; evidence that was withheld, corrupted and suppressed."