The urbane ex-director of the Central Intelligence Agency seemed a bit peeved.

Richard M. Helms had just spent a long morning with the House Assassinations subcommittee investigating the murder of President Kennedy, and "theyaasked me all sorts of questions about things in the past." The former CIA director spoke with a trace of exasperation, as though everyone must know that it is much too late to call back such stale ghosts,

Surely the subcommittee had been refreshing his recollection? a reporter asker.

"Not very successfully," Helms replied with a smile.

The House Assassinations Committee is likely to run into that problem repeatedly as it begins this week the first of two unprecedented sets of public hearings into the murders of President Kennedy and the Rev. Martin Luther King Jr. There will be trials that aren't defendants, hashing over dusty files and forgotten facts in an effort to resolve disputes that will newver be settled.

The committee hopes the exercise will be cathartic. Skeptics expect a circus.

"One of the reasons for the lingering doubts and suspicions in both these cases is that there has never been a trial in either one," says a committee spokesman."That means the American people never vicariously experienced what happened in those two prosecutions. A great deal of the frustration in these two cases probably stems from that fact and that fact alone."

A congressional committee, however, is rarely an impartial tribunal. It usually has a point to make, an ax to grind.

The theories of the "prosecution" that are about about to unfold appear to be radically different from what the backers of the committee had in mind two years ago when the House authorized the inquiries. The self-appointed revisionists of the King and Kennedy murders, such as the controversial Mark Lane who led the lobbying effort to create the committee, were counting on it to exonerate James Earl Ray, King's convicted killer, and Lee Harvey Oswald, Kennedy's presumed assassin. The critics were elated at the prospect of convicting, instead, the CIA for somehow engineering Kennedy's murder and the FBI for somehow arranging King's.

That is no longer likely. The demonology has changed again. The old answers are making a comeback, albeit with new trimmings.

"We're going to nail James Earl Ray to the cross," one committee member was quoted as saying of the hearings that begin tomorrow. As for Oswald, the committee reportedly has uncovered new information about his travels and contacts in Soviet Russia and in Mexico suggestive of ties withe the Soviet KGB rather that with the CIA.

The hearings this week will begin with King's slaying in Memphis in 1968.

"They're going to try to ruin James," predicts his brother, Jerry Ray. "They're going to try to destroy him . .To us, it's a crooked committee, an FBI-CIA committee."

The fireworks are likely to come Wednesday when Ray, serving a 99 year term at Tennessee's Brushy Mountain State Prison, is scheduled to testify ion the company of his lawyer, the ubiquitous Mark Lane.

At Brushy Mountain last month committee members and lawyers "told him they'd give him an hour to make an opening statement," Jerry Ray said in a telephone interview. "He's working on it now. He's going to tell how he excaped from Missouri State Prison (in 1967), where he went after he escaped, up to the present day.

"Then he's going to throw it open and let them ask what they want. He's going to stick to the facts and let them try to tear him up. Mark thinks he'll hold up pretty good."

There is, however, no firm understanding between the committee and Lane over, how long Ray can speak and how closely he must hew to chief counsel G. Robert Blakey's tightly "structured" plan to keep the first week focused on what happened in Memphis. Once here under subpoena, Ray might testify for three days. Or Committee Chairman Louis Stokes (D-Ohio) may cut him off the first morning. In that case, what Ray has told the committee in thus far unpublished interviews at Brushy Mountain may come tumbling unbidden into public domain.

"James Earl Ray has talked to us for over 28 hours on tape," a committee "spokesman" told reporters at a background briefing (the "spokesman" had previously been identified publicly as Blakey). "We have those transcripts on tape. In one sense, we have his body by virtue of his previous conversations with us."

Tomorrow's leadoff witness will be the Rev. Ralph Abernathy, another civil rights leader who was with King the day of the assassination. The curtain raiser will be devoted to outlining what King represented in American life, how he came to Memphis, and finally his deathat the Lorraine Motel on April

Abernathy has tlod reporters in Memphis he also wants to recount his belief that the FBI and Memphis police helped "conspirators" spirit Ray from Memphis after the shooting, an issue that the committee apparently doesn't intend to deal with until a final round of hearings on the murder in November.

Tuesday's session will produce a clinical examination of how and why King died, with testimony from a forensic pathologist whose name will be announced that morning.

The hearings will usually run from 9 a.m. to noon, hurried along by narratives from committee staffers and succinct questioning of most witnesses without any opening statements from them. There are likely to be only a few seats for the public. Admission for Ray's testimony Wednesday will be by ticket only. Security will be tight. Even Ray's lawyer, Lane, has had to sign a secrecy agreement not to divulge where Ray will be staying in Washington.

"There will be no chance taken that he does not get back to Tennessee," the committee spokesman said. "One thing we don't want is to have a repetition of what happened in Dallas" when Oswald was gunned down by Jack Ruby.

The murders in Dallas in November 1963, first of Kennedy and then of Oswald, will be explored at public hearings next month. But former CIA Director Helms, for one, ia skeptical about what that might establish.

"Nobody know today what Oswald represents," he said the other day outside the JFK assassination subcommittee's hearing room. "He's dead. His wife isn't telling the truth." On top of that, the former CIA director declared, "there's a whole unexplained period" concerning Oswald's life in Russia.

"This is the whole question, the whole thing," Helms said of what motivated Oswald. "It's never been resolved and it's obviously not going to be."

Whether Oswald had any ties with the KGB would never be known, Helms said, "unless the KGB tells you that."

"Or the CIA tells you" of CIA ties, a reporter asked.

"Oh, that's silly." the former CIA chief replied.