The House Assassinations Committee yesterday launched a painstaking set of hearings to explore whether the killing of the Rev. Martin Luther King Jr. was the product of either official or underworld conspiracy.

The Committee's chief counsel, G. Robert Blakey, said the public hearings, which will run through the end of November, will examine 10 facets of the conspiracy hypothesis, including lapses in police security on the day King was shot and the source of funds that paid for extensive travels by James Earl Ray, the itinerant robber convicted of King's murder, in the months before and after the assassination.

The hearings will constitute chapter two of the committee's probe into the King killing. Last August the committee spent three days questioning Ray, who now denies that he shot King, and tore holes in Ray's complicated alibi defense.

The committee's cross-examination of Ray was filled with the crackling drama of a tense courtroom confrontation. The new round of hearings, judging from yesterday's session, may be quite the opposite.

Blakey, the unit's lawyer, has set himself the task of reviewing, in detail, almost every question students of the King case have ever raised about the civil rights leader's death, from a single gunshot on the balcony of a Memphis motel on April 4, 1968.

In effect, the committee has embarked on a tedious game of chess with assassination buffs. This is necessary, Blakey said, because "these unanswered questions weave a sinister story."

As set forth by Blakey, the tale begins with Ray's escape from a Missouri prison 11 months before King's murder.

"Ray is broken out of prison, either as assassin or as patsy," Blakey said, summarizing the elements of the conspiracy theory. "He is given financial support, plastic surgery, a car and a gun, while arrangements are made for tacket out of the country and a false passport. Meanwhile, Dr. King is lured back to Memphis . . . his security is withdrawn, and he is felled by one deadly shot. The escape of the assassin is facilitated . . . Ray is caught, convicted or framed, but in any event, silenced."

Blakey said some, "but not many," of the elements that seem to support this theory can be dismissed quickly. He said the committee has found it unlikely, for example, that Ray had any official help in his Missouri prison break.

But other questions "could not be explained away," Blakey said, and will require detailed review.

Most of yesterday's session focused on what Blakey calls one of the toughest questions: the lapse in police security in Memphis that left King "virtually unprotected."

When King arrived in Memphis the day before his death, he was given a four-man security detail by the Memphis police department. That detail was terminated the next day, just one hour before King was shot.

Frank Holloman, who was the city's director of fire and safety in 1968, testified that the security squad was sent home because King said he did not want police protection.

Holloman, who noted repeatedly that he could not recall the specifics of the situation, said King protested the police security arranged for him when he arrived in Memphis.

The next day, according to committee evidence, the leader of the security detail told his superiors that King's group had tried to lose its police escort on a drive through the city.The officer's superiors then told him to disband the security force, the evidence showed.

The committee also questioned Edward Redditt, a black former Memphis police detective who was assigned to surveillance of King, but was relieved of the job shortly before the fatal shot was fired.

Redditt figures prominently in a book by Ray's lawyer, Mark Lane, which lays out much of the evidence for Lane's claim that Ray was framed. Lane's book says Redditt was the Memphis policeman responsible for guarding King and raises questions about his last-minute removal from his post.

In his testimony yesterday, Redditt said his mission was to spy on King rather than to protect him. He said he was removed from his surveillance post for his own protection, because black groups had made threats on his life.

Redditt said he had been misinterpreted or misquoted in press interviews in which he was said to have claimed he was in charge of King's security in Memphis.

The committee also presented evidence, including a long taped interview with a Mexican prostitute whom Ray patronized to determine whether Ray was prejudiced against blacks. Blakey said evidence on the question is not conclusive.