When the House Assassination Committee released its report last month, its most perplexing section concerned alleged organized crime involvement with the killing of John Kennedy. Santos Trafficante and Carlos Marcello were fingered as "the most likely family bosses" to have participated in any plot, but then the ambivalent report termed the notion "unlikely."

Linking Marcello to JFK's death was an obscure private eye named Edward N. Becker, a shadowy figure who has passed in and out of organized crime circles as a shamus and anonymous researcher of books. Who is Becker?

He's a 57-year-old, soft-spoken man who today lives in Las Vegas with his second wife. He's currently involved in business with a former assistant attorney general of the U.S., Washington-based attorney Jerris Leonard. And Becker is not delighted his name surfaced in the House report.

"I expect some kind of retribution," Becker says today. "The committee said, "We're doing everything in the world to protect you." I didn't believe it. Of course I'm worried."

In 1955 Becker signed on as public relations director for the Riviera Hotel in Vegas. His milieu was gambling and men whose occupations were vague, he says, and he eventually helped piece together an NBC "White Paper" on organized crime in 1966. He also helped gather information for the books Green Felt Jungle and the Grim Reapers, both billed as exposes of organized crime.

Becker says he was in Louisiana in September of 1962 working undercover for a finance company investigating Billie Sol Estes when he struck up a friendship with Carl Ropolo, a Shreveport oil geologist well-liked by Marcello according to the House report. The two men visited Marcello at his estate near New Orleans. In the course of a long evening of drinking scotch, Becker remembers Marcello cursing the Kennedy brothers and talking vaguely of trying to kill the president.

Marcello denies that.

That scene (without Becker's name) made its way into Ed Reid's book, The Grim Reapders, which led the House committee to Becker, who talked with a committee staffer by phone but refused to testify because he feared the arm of organized crime as well as the wrath of the FBI. The Bureau, according to the House report, worked hard to discredit Becker instead of investigating the validity of his information.

Becker and Reid had a falling out - "I'm looking for Reid the same way Carlos is looking for me," says Becker with a grim laugh. Currently Becker is helping Leonard, former head of the Law Enforcement Assistance Administration during the Nixon administration, run an Arlington company that resplices used computer paper for resale. And they are discussing performing some public relations work to save the Everglades. Which is a long way - Becker hopes a very long way - from the business of assassination. CAPTION: Picture, no caption, UPI