Alfred Kassab pursued his son-in-law for nine years. Now he has Dr. Jeffrey MacDonald where he wants him, in U.S. District Court in Raleigh, on trial for murder.

The prosecution has completed its case against MacDonald, 35, an emergency room physician in Huntington Beach, Calif... He is charged with the stabbing and bludgeoning deaths of his pregnant wife and two young daughters in February 1970.

At the time of the murders MacDonald was a Green Beret medical officer, living with his family in officers' housing at Fort Bragg, N.C...

MacDonald told base investigators at the time that he and his family were attacked by four intruders who entered the house while he was sleeping on the living room couch. MacDonald said he awoke to hear his wife, Collette, screaming, "Jeff, Jeff, help me. Why are they doing this to me?" His oldest daughter, Kimberly, 5, was yelling, "Daddy, daddy," he said.

MacDonald said he rose to his elbows and met four attackers, three men and a woman wearing a floppy hat.According to MacDonald, one of the attackers was carrying candles, and chanting, "Acid and rain are groovy, kill the pigs." After a brief struggle in the living room, MacDonald was stabbed and knocked unconscious, he said.

When he regained his senses, according to his account, MacDonald staggered to the master bedroom, where he found his 26-year-old wife lying on the floor in a pool of blood. She had been clubbed and stabbed more than 40 times. MacDonald unwrapped his pajama top, which he said had become twisted around his wrist during the fight, and put it on his wife to try to keep her from going into shock. By his account, he then went to Kimberly's bedroom, and to 2-year-old Kristen's bedroom to attempt to revive them. Both had been similarly stabbed and beaten.

MacDonald called the operator to ask for help before passing out beside his wife.

When military police arrived, only Jeffrey MacDonald was alive. He was carried to Womack Army Hospital, where doctors treated him for several superficial puncture wounds and another more serious wound, which had caused a partial collapse of his right lung.

Alfred and Mildred Kassab, Collette MacDonald's stepfather and mother, rushed to MacDonald's bedside. The Kassabs had liked MacDonald since he began dating Collette after they met at their Patchogue, N.Y., high school, in Long Island.

"He was an All-American guy," Kassab said. "I really liked him. He was a smart boy who was obviously going places." Kassab said he was proud of MacDonald's initiative, noting that MacDonald worked his way through college at Princeton and medical school at Northwestern University.

When Army investigators announced they were bringing charges against MacDonald, Kassab denounced the Army. He said they had botched their investigation and were making a scapegoat of MacDonald to put the Fort Bragg community at ease.

Army investigators said the physical evidence at the house conflicted with MacDonald's story.

They noted that the pajama top MacDonald said he was wearing during the struggle had only one spot of his blood on it, while it was soaked with his wife's.

They also contended that the 48 holes in the bloody pajama top could be made to correspond to the 21 stab wounds found in Collette MacDonald's chest. The Army agents further noted that although MacDonald said his pajama top was ripped in the living room, there were not many fibers from it there. Instead, they said, most fibers from the pajama top were found under Collette's body and in the children's bedrooms.

According to the government, MacDonald flew into a rage during a fight with his wife, and killed her. They say he murdered the children as a cover-up after one of them witnessed the crime.

At the closed Army hearings, MacDonald's attorneys successfully argued that the government's case was flawed because investigators had handled the crime scene badly.

The Army board called the charges against MacDonald not true, and suggested that the Army look elsewhere for the assailants. MacDonald was granted an honorable discharge, and moved to New York, and then to California to rebuild his new life as an emergency room doctor.

Alfred Kassab was not allowed to attend the closed hearings, and he did not get transcripts of the proceeding until late 1970. Up to then he relied upon MacDonald for his information about the incident.

When Kassab read the transcripts, he became very disturbed. "There were too many inconsistencies in his story," Kassab said. "It just didn't make sense."

Kassab then began what he called "a legal vendetta" aimed at getting the federal government to prosecute MacDonald for the murders. In addition to his work as an executive with a Cranbury, N.J., egg company, Kassab spent 30 to 40 hours a week lobbying Justice Department officials, writing letters, tracing leads and consulting lawyers about the case. At one point, he visited every member of Congress to give them a written account of the case.

In 1974 Kassab attempted to swear out a murder warrant in federal court, and the government was pressured into convening a grand jury to hear the case. In January 1975, MacDonald was indicted for the murders. He faces a life sentence if convicted.

MacDonald says he has been unjustly pursued by two forces. "What you have here," MacDonald said recently, "is a mid-level bureaucracy that has been running amok, and an aggrieved stepfather-in-law."

The case has been tangled in the courts ever since the indictment was handed down. The U.S. Supreme Court has heard arguments about the case twice, as MacDonald's attorneys said he was being exposed to double jeopardy, and that his right to a speedy trial was being violated.

In both instances the justices ruled that MacDonald would have to stand trial. However, they reserved ruling on the issue of a speedy trial until MacDonald had been judged by a jury of his peers.

As the trial approaches its fifth week, spectators are beginning to crowd the courtroom.

Throughwout the drama, MacDonald has sat calmly at the defense table with his lawyers, advising them about the medical testimony being offered against him. He has appeared to the model of an emergency room doctor, a man accustomed to operating under pressure. CAPTION: Picture, DR. JEFFREY MACDONALD...on trial in murder of his family