The House Assassinations Committee concluded its public hearings on the murder of the Rev. Martin Luther King Jr. yesterday in an acrimonious session with a heavily guarded, somewhat bruised brother of convicted assassin James Earl Ray.

Testifying with a black eye he suffered in an altercation in St. Louis Monday night, John Ray, 47, found himself questioned primarily about a series of bank robberies beginning with a 1967 holdup in Alton, Ill. The committee concentrated on the heists so much that it neglected to ask Ray whether he had anything to do with the assassination. (Ray's attorney said afterward that his client, if asked, would have denied it.)

John Ray denied taking part in any of the holdups, including the one for which he was convicted in 1971 and sentenced to 18 years in federal prison. Paroled in September, he insisted that he was the victim of a government-engineered "fix."

The hearing was marked by a series of clashes throughout the morning between Ray's lawyer, James Lesar, and committee Chairman Louis Stokes (D-Ohio).

Shouting Lesar down in mid-sentence at times, Stokes repeatedly lost his temper in the face of the defense lawyer's garrulously persistent accusations that the committee was indulging in "sheer guilt by association" and other prejudicial tactics.

At one point after he'd been overruled, Lesar protested to Stokes, "You have not let me get a word in edgewise. I think it's sickening."

"You are a disgrace," Stokes replied.

At that, the defense attorney called for a recess and challenged Stokes to repeat himself "outside, where you do not have congressional immunity." The brouhaha finally ended with Stokes turning over the gavel to Del. Walter Fauntroy (D-D.C.) and withdrawing his "regrettable" remarks from the record.

The debate over the committee's methods, however, continued throughout the hearing. In an opening statement, committee lawyer James L. Wolf dwelt heavily on the notions that John Ray might have helped his older brother, James Earl Ray, escape from prison in 1967 and then have taken part in the $27,230 Alton bank robbery, providing James with the funds that carried him through the assassination.

King was assassinated in Memphis on April 4, 1968. James Earl Ray, now serving a 99-year term for the murder, was captured in London some two months later.

Yesterday's questioning of John Ray began with committee lawyer Mark Speiser asking him about his "racial attitudes" on the theory, he said, that the Ray family was "very close" in 1968 and that "John Ray's attitudes would be indicative of James'."

Lesar protested sharply, denouncing the approach as "sheer guilt by association," but Stokes overruled him.

Called to answer, Ray described himself as "a mild segregationist" who acknowledged that he might well have made some harsh remarks about King after his death in 1968. An FBI report, based on an April 22, 1968, interview of John Ray at his Grapevine Tavern in South St. Louis, quoted him as saying:

"What's all the excitement about? He only killed a nigger. If he had killed a white man, you wouldn't be here. King should have been killed 10 years ago."

Asked if he made those remarks. Ray said he might have, but was "probably drunk" at the time.

"I ran a tavern in a racist neighborhood," he said, adding that "when I get drunk, I don't know what I'm doing."

Guarded by federal marshals after his arrest in St. Louis Monday night for having "wandered" into the wrong apartment, where he got the black eye, Ray denied any clear understanding of his brother's racial attitudes in 1968, although he described both himself and James at the time as "strong supporters of George Wallace" in his American Independent Party presidential campaign that year.

Similarly, John Ray disclaimed any recollection of having visited James Earl Ray at the Missouri State Penitentiary, as prison records reflect, on April 22. 1967, the day before his brother's escape. John Ray also denied helping his brother in the escape effort, and said he wasn't even aware he had escaped until the next year, after the King assassination.

Turning to the July 13, 1967, robbery of the Bank of Alton by two masked gunmen, committee counsel Speiser said it was similar to five other post-assassination bank robberies in which committee informants have implicated John Ray and, on one occasion, Jerry Ray, another brother.

The committee also said that Jerry Ray had admitted to a witness it agreed to keep anonymous "that James and John did indeed commit the Alton holdup." Committee lawyers said that the day after the robbery, James Earl Ray began "to spend money quite freely -- $210 for a used automobile on July 14, $150 for two months' rent on arrival in Montreal, $50 for a prostitute in Montreal, $200 for new clothes." In addition, John Ray left for California later that month, coming back with nearly $30,000 in cash.

John Ray said he couldn't speak for his brother, and he flatly denied taking part in the Alton robbery or any of the others. He accused the committee of relying on the word of unreliable witnesses who would "testify to anything."