Six years after the 1968 assassination of the Rev. Martin Luther King Jr., the FBI received an allegation that a Missouri stockbroker was "the individual who made the payoff of James Earl Ray after the killing."

The Federal Bureau of Investigation never investigated the report, assertedly because it was simply consigned to the informants' files in its St. Louis office and never properly distributed.

"It fell between the cracks," FBI spokesman Homer Boynton said yesterday. "All I can say is 'nobody's perfect.'"

The stockbroker and a lawyer friend who was also named in the same claimed conspiracy have died. The allegation concerning them came from a former St. Louis automobile parts dealer, Russell G. Byers, who said he himself had been offered "either $10,000 or $20,000" by the same two men to kill King.

Byers' account accidentally came to the government's attention in March when FBI agents in St. Louis reviewed their files for any records pertaining to Byers as a result of his implication in an art theft. (Missouri prosecutors later dropped those charges)

FBI documents on the matter were made public this week under the Freedom of Information Act to Harold Weisberg, an author-investigator of assassinations, and others. The principal record was a heavily censored memo written by an FBI agent and dated March 19, 1974, concerning a conversation in the fall of 1973 one of his informants had with Byers.

The memo quoted the unidentified informent as stating that during the 1973 conversation:

"Beyerh [sic] talked freely about himself and his "business, and they later went to (deleted) where Beyers told a story about visiting a lawyer in St. Louis County, now deceased, not further identified, who had offered to give him a contract to kill Martin Luther King."

According to the memo, Byers added that "also present was a short, stocky man who walked with a limp. (Later, with regard to this latter individual, Beyers commented that this man was actually the individual who made the payoff of James Earl Ray after the killing.)"

The memo continued:

"Beyers said he had declined to accept this contract. He did remark that this lawyer had Confederate flags and other items about the house that might indicate that he was 'a real rebel.' Beyers also commented that he had been offered either $10,000 or $20,000 to kill King."

The short, stocky man with the limp was not named in the documents made public this week, but he has been identified by sources as John H. Kauffmann, a stockbroker and businessman from Imperial, Mo. The lawyer reportedly was John H. Sutherland, a business associate and neighbor of Kauffmann's, who died in 1970.

There was no indication of why the 1973 conversation was not set down, along with the other matters deleted from the memo, until the following March 19. Kauffmann had died 18 days earlier, on March 1, 1974.

In any case, the document lanquished in FBI files until it was found last spring and forwarded to the House Assassination Committee which took testimony from Byers at a brief appearance in early Mary. He reportedly told the committee then that he had been offered $50,000 to help arrange King's assassination.

None of these allegations was known to the Justice Department task force that reviewed the FBI's investigation of the King murder in 1976-77. The task force strongly endorsed the conclusion that Ray was the lone killer and that no conspiracy was involved, but acknowledged "the sources for Ray's funds still remain a mystery today."

Despite that, both members of the task force and critics of the government inquiry, such as Weisberg, discounted the allegation that Ray might have been paid off after the assassination.

"If Ray had been paid any sum, as little as $100, he would not have been caught," Weisberg declared. "When he was in Lisbon (after the assassination), he was just $100 short of boat passage to Rhodesia - a country that had no extradition treaty with the United States - and so he had to leave Portugal to go back to England."