Convicted murderer Jeffrey MacDonald remembers the day he met his biographer, Joe McGinniss.

"He's a visiting columnist with the Los Angeles Herald Examiner, and one day he comes down to Huntington Beach to do a story about me. This is 1979, a few months before the trial. We have a nice day. I buy breakfast -- Joe hasn't picked up a tab in his life. We run on the beach together. He drinks my beer, we have a nice conversation and he says, 'Well, I think I have enough material for a column.'

"I said, 'Joe, let's talk about the facts in the case. Let's not talk about the condominium, let's not talk about the length of the boat and let's not talk about my girlfriend, okay?'

"So about a week later he calls and he says, 'Have you seen the column?'

"I said, 'No.'

"He says, 'Well, okay, don't get upset when you read the column . . . It's not bad. It's just that it may not be what you want.'

"I buy the paper and I read the column and it's about the boat, it's about my blond stewardess girlfriend and it's about the condominium, which is a lousy three-bedroom condo on the water that cost me $50,000 when I bought it in 1971. At the time Joe met me I owed $21,000 on the condo. I then took out a $130,000 second mortgage to pay Bernie [Bernard Segal, MacDonald's defense attorney in 1979] . . .

"I call him back and I say, 'Joe, this is a piece of crap.' Now get this -- here's his exact quote. He says, 'Jeff, I wrote a good column but the editors changed it because they say the people in L.A. only want fluff.'

"I said, 'Joe, I'm really disappointed. I thought we had a whole different kind of relationship.' . . . Anyway, I called back Bernie, who had been really pushing me to do a book because we needed the money for the defense, and he said he knew Joe from Philadelphia and he was a great guy and maybe what he said about the column was true.

"Well, I look back on it now and bells should have gone off in my head. Everything that has happened in my life with Joe McGinniss has been an enlargement of what happened that first day."

McGinniss, informed of MacDonald's account, said: "Every element of that story is untrue. I could write anything I wanted to. Nobody changed a word of it. He never called to complain. And we didn't spend a whole day together."

Jeffrey MacDonald, 41, the former Green Beret doctor serving three consecutive life sentences for murdering his pregnant wife and two daughters in their Fort Bragg, N.C., apartment on Feb. 17, 1970, lives in a 7-by-9 cell at the Federal Correctional Institute at Bastrop, haunted by one of two horrible truths.

Either he did the unspeakable, or he didn't but people think he did.

The body of evidence against him, so overwhelming at trial, has recently been challenged by a body of new evidence uncovered since his 1979 conviction. It lacks the weight of the earlier evidence, and much of it is self-contradictory and riddled with credibility gaps. But for all that, it at least raises anew the possibility of MacDonald as victim, not murderer.

On Monday, MacDonald's lawyers went into U.S. District Court in Raleigh, N.C., to argue for a new trial on the basis of the new evidence -- two confessions, 25 corroborating statements and seven pieces of new physical evidence. If granted, it would be the fifth major reversal in a case that has gripped the national psyche on and off for 15 years.

And why not? The story, either way, is tragedy writ large. MacDonald, the golden boy, charming with men, seductive with women, bright, articulate and overachieving, with a blemish-free family life (at least on the surface), everything to live for, going berserk one night and murdering his family in a fit of -- what? Suppressed rage toward women? Drug abuse? Latent homosexuality? Narcissistic amorality?

Joe McGinniss' best-selling book "Fatal Vision," and last fall's NBC-TV movie based on it, suggested all of that. After researching the case for three years, McGinniss concluded that MacDonald was hopped up on diet pills, overworked, deprived of sleep, resentful of his wife's growing independence and, one night, he cracked. He killed her, murdered their 2- and 5-year-old daughters in the most horrible way, then staged an elaborate cover-up to make it look as though a band of drug-crazed hippies had broken into the house, knocked him unconscious and committed ritualistic murders.

The investigators didn't believe MacDonald's story (the crime scene bore no traces of outside intruders or of much violent struggle), neither did the jury, and neither, finally, did the man MacDonald sought out to write his biography. Now, thanks to McGinniss, neither do most of the 60 million people who saw "Fatal Vision" on television -- the highest rated nonsports show on NBC last year. Before the movie aired, a Newsday poll showed that only one person in five in MacDonald's hometown of Patchogue, Long Island, thought he was guilty. Afterward, one in two thought he had done it.

What galls MacDonald, who is suing McGinniss for fraud and breach of contract, is that he brought this latest round of bad publicity -- "this trashy book and movie, full of flat-out factual inaccuracies, that paints me as a vicious, chauvinistic, uncaring, unfeeling monster" -- on himself. It was he who broached the idea of a book to McGinniss, even after the unhappy episode with the column.

"It was Bernie's idea," he says. "We needed the money for the defense, and he felt we should get our story out because we were the victims of government persecution."

Overtures to Joseph Wambaugh, among other authors, had gone nowhere, so a deal with McGinniss was struck. He and MacDonald became fast friends, roomed together during the trial at a rented frat house in Raleigh. After the conviction, McGinniss lived at MacDonald's condo, while MacDonald, in prison, tape-recorded at McGinniss' urging his innermost recollections of his sex life with his wife and many women friends.

"Joe is a master at ingratiating himself to you," he says, "living in your house, eating your food, drinking your booze, pawing through your personal records and appearing to be this up front, simple East Coast guy who loves the Knicks and the Mets. You know. I mean, it's awful."

Said McGinniss: "That's complete garbage. He was leading me on for all those years by trying to persuade me to put my reputation on the line in defense of something indefensible -- his innocence."

Though McGinniss has said on the talk show circuit that he concluded MacDonald was guilty around the time the jury did -- in August 1979 -- MacDonald says McGinniss continued for years afterward to lead him to believe he was his biggest supporter.

"What . . . were those people thinking of?" McGinniss wrote MacDonald a month after the verdict. "How could 12 people not only agree to believe such a horrendous proposition, but agree, with a man's life at stake, that they believed it beyond a reasonable doubt? In 6 1/2 hours?"

MacDonald now says he believes McGinniss has "always been negative . . . my particular life style and my persona always grated on him." But, he says, it could not have come as a greater shock when he first found out.

It was in the summer of 1983. MacDonald was being interviewed by Mike Wallace for a "60 Minutes" piece pegged to the publication of "Fatal Vision," which was due out in a few months.

Wallace, cameras off, spent an hour warming MacDonald up. They traded small talk as they walked the grounds of the medium security facility, which looks like a junior college campus save for the two 12-foot chain link fences, protected by seven bands of razor wire.

"I remember him telling me he'd interviewed my mother and predicting that when the segment aired, she would be America's sweetheart," MacDonald says. "Anyway, eventually we go into the warden's conference room and Wallace says, 'Ready?' I said, 'Sure.'

"The cameras start rolling and he looks at me and he says, 'How would you feel if I told you Joe McGinniss says you're a homicidal maniac?' Opening question! Or words to that effect. There may have been different adjectives.

"I looked at him and broke out into a sweat. I said, 'This is a joke.'

"He said, 'No, Jeff.'

"I said, 'Joe McGinniss, the writer that's been dealing with me for the last four years?'

"He said, 'That's right.'

"I said, 'I don't believe you.'

"He said, 'I have the manuscript right here.' Then he reaches into his briefcase and puts the manuscript on the table.

"I was devastated."

When MacDonald talks of McGinniss -- when he vents his anger and sadness at being taken in by what he calls an attractive, ingratiating, winning personality -- there are unmistakable echoes of McGinniss' descriptions of MacDonald. The two have not spoken since the Wallace interview.

MacDonald is suing McGinniss for $15 million. McGinniss is countersuing for "not less than $100,000." Meantime, MacDonald has received $76,000 as his share of McGinniss' book and movie proceeds. But he claims McGinniss has earned more than $1 million, and that their contract called for him to turn over between 30 and 40 percent of his earnings to MacDonald. McGinniss says that once MacDonald sued, the deal was off. It's all in the courts.

In his interview in prison, MacDonald claimed numerous "flat-out lies" in the McGinniss book, of which three stand out:

* "The crusher -- the amphetamine abuse theory." MacDonald has said ever since 1970 that he had taken three to five diet pills in the month preceding the murder. McGinniss theorized that he had been taking three to five pills a day, and that this may have precipitated a violent rage. Drug tests on MacDonald taken after the murder were negative. "I'm Mr. Straight," MacDonald says. "My friends laugh at me. I've never even smoked a joint."

McGinniss said he never concluded that MacDonald had been abusing diet pills, but left open the inference based on MacDonald's weight loss (12 to 15 pounds in the month before the murder).

* In one of the most damaging scenes in the book, McGinniss described MacDonald threatening to "crush the skull" of a 10-year-old son of a girlfriend because he was acting up on a boating trip. MacDonald calls the description "a total fabrication" and says the incident was "normal horseplay." Besides the murder, the incident is the only recorded example of MacDonald showing a violent streak. McGinniss quotes the boy recalling the "fire in MacDonald's eyes," but does not name him. MacDonald says the boy, now a young man, doesn't want to talk, but that his mother, who witnessed the incident, confirms MacDonald's account.

McGinniss said: "There were three people on that boat -- MacDonald, the mother and the kid. I talked to the mother and the kid. It was their recollection that produced the anecdote in the book."

* McGinniss' psychological portrait of MacDonald is buttressed by the report of Dr. James Brussels, who examined the suspect just before the 1979 trial. "I had taken five psychiatric exams before that," MacDonald says, "three of them by prosecution psychiatrists, and passed them all with flying colors, but the government wouldn't let us introduce them unless we agreed to be tested by Brussels. McGinniss told me at the time I was crazy to take it, it was a setup.

"Anyway, I go into the exam and this guy is 80 years old, he's just had a stroke and he's drooling from the corner of his mouth. He thought he was in Maryland. He didn't know he was in North Carolina. After a while he takes out a typed piece of paper and starts asking me some questions like, 'Who wiped the telephone?' I said, 'Where did the questions come from?' He said, 'That nice little man with glasses.' I said, 'You mean that beady-eyed little guy, Brian Murtaugh the chief prosecutor ?' He said, 'Yeah.' I said, 'I've had enough of this,' and walk out."

The Brussels report, full of damaging assertions about MacDonald ("He said I was a homicidal maniac with homosexual tendencies," MacDonald says), was never introduced into evidence, but McGinniss cited it in his book. "Unbelievable," says MacDonald.

The case against Joe McGinniss, of course, is not the case MacDonald most needs to win. "The book didn't convict Jeffrey MacDonald. The movie didn't convict Jeffrey MacDonald," says prosecutor Murtaugh. "The facts are what convicted MacDonald."

There are facts -- such as the discovery of fibers from MacDonald's pajamas underneath one daughter's fingernail; such as the fact that in a two-family dwelling, the neighbors were not awakened by any commotion that night; such as the fact that MacDonald's description of the crime does not jibe with the absence of any conclusive physical evidence of intruders -- that no quantity of new evidence can undo.

But there is another unmistakable fact about the MacDonald case. It was botched by investigators from the start. Key bits of physical evidence -- a piece of skin taken from underneath his wife Colette's fingernail; seven fingerprint negatives that were unknown but "typable"; allegedly bloodstained clothing given by one of the women who confessed to the murder to a friend shortly after the killing -- were either lost or destroyed. MacDonald and his lawyers did not know of their existence until after the conviction, when they probed through government files under a Freedom of Information Act request.

And there is also the fact that two women, both known drug abusers who lived in the Ft. Bragg area in 1970, have confessed to the crime, and a third man confessed to friends. Their stories contradict one another, and may well be the ravings of publicity-seeking "loonies," as Murtaugh says, but parts of each story have been corroborated by more than 20 seemingly disinterested witnesses. None of the confessions or corroborations was allowed to be heard in the 1979 trial.

"I have no doubt that if another jury hears my case, I'll be found not guilty," says MacDonald. "The only question is whether I win this appeal for a new trial in Raleigh, or whether I'll have to go to the Fourth Circuit in Richmond."

As the interview ended, MacDonald handed over 12 documents about the case (in addition to four legal briefs his lawyer had already mailed). To each one had been stapled a torn, one-third sheet of lined paper on which MacDonald had written out annotations: "The most complete article ever written about the new evidence"; "This is the entire 1983 Spring issue of the U. of Penn Law Review, all about my case, entitled, 'How Things Should Not Work' "; and so on.

He passes his hours in prison working on the case, doing his job as a dorm janitor and studying medicine (the federal system does not permit doctor inmates to practice). After the movie aired, his mail volume shot up to 100 letters a day -- most of it favorable, he says, but some incredibly vicious. It's back down to 30 a day now. He tries to answer most of it.

He runs five miles four days a week in his silver Nikes, lifts weights four days a week and has a powerful set of biceps and forearms to show for it. "Five-foot-ten, 182 pounds, hazel eyes," he reels off when the question of his size comes up. His sandy hair is gray now, combed back and thinning a bit. His face has a well-preserved look, his prison khakis are neatly pressed.

His voice occasionally rises in the midst of animated conversation, but his tone is more subdued than it was during the 1970s, when, he says, his "anger" led him to strike a posture of cockiness on the witness stand and in public -- a posture he says he now regrets.

MacDonald says he's sustained by the "incredible number of people" on the outside who believe in him. They run the gamut from his old Princeton roommate to numerous doctor and policemen friends in Huntington Beach to ex-girlfriends. These friends, he says, have contributed about a quarter of the $700,000 he figures he has spent so far on his defense. "The expense would be much higher," he says, "but my lawyers and detectives believe in the case."

Well then, did he or didn't he?

MacDonald is personable, bright, to the point. Yet some of his answers seemed programmed -- his contrition about being cocky on the witness stand, for example.

At the end of the allotted time, one final question was posed -- whether, given the fact that his own lawyer's brief argues that trauma can induce amnesia, he hadn't ever awakened in a cold sweat in the middle of the night in the past 15 years and wondered if he'd done it and blocked it out.

"No, no, no. Never on that," he said. "My struggle through the 1970s was of a different sort. It was that I was alive and my family was dead and how could I be the good person I think I am, and as honorable as I think I am, and not defended my family better than I did? I ended up relatively lightly wounded, though I did have over 17 stab wounds and multiple head wounds, and that's in the record. Ray Shedlick [his detective] will be happy to verify that . . ."