For five months, Rep. Frederick W. Richmond (D-N.Y.), a leading House liberal and one of its richest members, has been under investigation by a federal grand jury in Brooklyn that is probing his personal and financial activities.

The case has stirred considerable interest in New York but relatively little in Congress where Richmond is chairman of the agriculture subcommittee overseeing the food stamp program. Richmond and his spokesman have refused to comment on the probe.

The grand jury is known to be focusing on at least three allegations:

* Whether Richmond knowingly used his influence to help an escaped Massachusetts convict get a job on the House payroll under an assumed name. The man is in custody again after being arrested for male prostitution while in possession of Richmond's car in New York.

* Whether Richmond or his campaign aides, by using employes of the Walco National Corp., of which the multimillionaire congressman is a director and major stockholder, in his 1978 and 1980 reelection campaigns, violated federal election laws.

* Whether Richmond asked his staff aides to purchase drugs for his use.

The U.S. attorney for Brooklyn is attempting to get the convict, Earl W. Randolph Jr., to testify before the grand jury about Richmond's activities, according to a Boston lawyer who represented Randolph. Congressional sources say Richmond bypassed standard patronage procedures to obtain a job for Randolph under an assumed name with the House doorkeeper. Details, Page A7.

In July, 1980, Randolph, a longtime acquaintance of Richmond, was serving an 18-year sentence for assault with intent to kill and had a history of drug abuse when he escaped from a Massachusetts halfway house by diving through a third-floor glass window.

Six months later, aided by Richmond's recommendation, he went on the payroll of the House doorkeeper under an assumed name, John McLoughlin. House records show he worked in the House folding room from Jan. 5 to Feb. 28, 1981.

In early 1981, Randolph lived for a time under the name McLoughlin at 1014 22nd St. NW, sharing an apartment which Richmond personally arranged. After a run-in with a fellow tenant, Randolph moved out but only after Robert J. Welden, the building owner, told Richmond that he would "call the sheriff," according to Welden.

The grand jury is investigating whether Richmond knew Randolph was a fugitive last year when aiding him in getting the House job and the apartment under the false name. Knowingly aiding an interstate fugitive is a federal crime.

Randolph, as John McLoughlin, was arrested in New York City at 9:15 p.m. March 25, 1981, for male prostitution after he reportedly solicited an undercover policeman, suggesting a sexual act in the back seat of a car that belonged to Richmond.

At the police station, Randolph showed officers his identity card as an employe of the House doorkeeper and told them that he worked for a congressman. He reportedly gave Richmond's Washington telephone number and, in a phone conversation with police, Richmond confirmed that "McLoughlin" had permission to use Richmond's automobile.

When police asked Richmond that night if "McLoughlin" worked for him, sources said the answer was "not exactly."

After a check of fingerprints and other information, police established the prisoner's identity as Randolph, and he subsequently was returned to prison in Massachusetts.

At the time of Randolph's New York arrest in March, 1981, Richmond press aide Michael Kahan said, "the first we ever heard about this McLoughlin's record was after it was discovered by the police," according to press reports.

At that time, according to these reports, Kahan said McLoughlin had been "referred to Fred by friends in Boston."

Randolph, 28, a Massachusetts native who has known Richmond at least five years, is being held temporarily in the federal penitentiary in Danbury, Conn., as a potential grand jury witness.

Randolph's attorney, Richard Wynne, said recently that prosecutors could pressure Randolph by making parole difficult.

Randolph turned down a request by The Washington Post for an interview.

Brooklyn U.S. Attorney Edward Korman and his staff refuse to comment on the matter.

Kahan said last Thursday that Richmond's lawyers have advised him not to answer questions on matters under investigation.

Four years ago, Richmond was charged with one count of sexual solicitation here after an incident in 1977 involving a young boy who complained to his parents that Richmond had made sexual overtures when the boy delivered groceries to Richmond's home. Months later, an undercover policeman carrying a tape recorder reported that Richmond made a similar overture to him.

After being indicted, Richmond subsequently acknowledged that he "had made solicitations with the payment of money" to two males. The charges were dropped after Richmond agreed to undergo counseling.

In a letter to his constituents on April 6, 1978, Richmond said he had no "logical explanation" for the incidents and was seeking "appropriate professional advice."

Later that year, after House colleagues and New York political allies had rallied around him, Richmond won renomination and was reelected with 77 percent of the vote.

Now, New York City political leaders, including Mayor Edward Koch and Democratic party leader Meade Esposito, have asked publicly for Richmond's resignation, and several House colleagues have told him privately that he cannot survive the current scandal. Richmond has told friends and constituents that he will seek election to a fifth term.

Richmond press secretary Kahan said Friday that the congressmen would spend today in New York meeting with his staff to discuss the coming campaign.

At the time of Randolph's March 25, 1981, arrest, only one daily New York newspaper, The Daily News, carried a story, and that was two days later. There was no follow up for almost a year by newspapers in either New York or Washington, until Daniel W. Lehman, a reporter for the small weekly, The Brooklyn Paper, wrote the first of several articles about the incident. The New York Times, which late last year had begun publishing stories about Richmond's campaign fund and corporate activities, subsequently picked up the Randolph story.

Federal investigators got into the case late last year and have interviewed several former members of Richmond's staff and Massachusetts penal officials. They have not yet questioned officials of the House of Representatives, according to congressional sources.

It is unclear when the millionaire New York congressman and the Boston laborer first met.

A Massachusetts state document, lists Randolph as having worked briefly in 1972 for the National Casket Co., Cambridge, Mass., as a driver. National Casket at the time was a subsidiary of Richmond's Walco National Corp. In 1972, Randolph would have been 18 years old.

In 1975, according to the same document, Randolph is listed as a driver for two months for the "Richmond Foundation" in New York City. The Frederick W. Richmond Foundation in New York, is headquartered in the same Fifth Avenue building as Richmond's company.

During 1976 and 1977, according to the document, Randolph worked at the Coastal Dry Dock Corp., located at the Brooklyn Navy Yard. That facility is in Richmond's congressional district and the president of Coastal Dry Dock is one of Richmond's chief campaign supporters and fund-raisers.

On May 18, 1977, according to Massachusetts records, Randolph was convicted in Suffolk County Superior Court in Boston on three charges, the most serious of which was "assault with intent to murder."

Randolph was sentenced to 18 years at Concord Prison, which under Massachusetts procedure meant he could be eligible for parole in two years.

Late in 1977, persons identifying themselves as members of Richmond's staff reportedly began calling state corrections officials, attempting to get Randolph transferred to medium or minimum security facilities.

Such calls are not unusual. Officials, sources said, receive many such requests from local politicians and several believed that Randolph or his family must have been constituents of the New York congressman.

In 1978, Randolph served some time at the Warwick Prison Camp, a forestry camp with about 40 inmates and 16 corrections officers which is considered a minimum security facility. During his time there, Randolph reportedly received telephone calls from Richmond's office and letters from the congressman's office that contained money.

In a subsequent May, 1980, report on Randolph's stay at Warwick, Paul St. Armand of the Warwick Classification Committee, wrote, "Mr. Randolph appears to have manipulative strength politically and has gained favors far beyond what his behavior warrants."

The Brooklyn Paper quoted a former Warwick corrections official who said that during 1979, "I personally called the congressman's office on occasion and hooked Randolph up with them. . . . It's Warwick a small place, and soon everyone knew that Randolph had an 'in' with a congressman."

In early 1979, Randolph was transferred to Brook House in Boston, a halfway house for prisoners who are in line for parole. He was entered in a work-release program at the New England Casket Co., which supplied caskets to the National Casket Co.

In May, 1979, Randolph was paroled. Three months later, however, he failed to report in to his parole officer, as required by law, and was declared in violation of parole.

In October, 1979, according to available Massachusetts records, Randolph was recaptured and returned to prison.

In April, 1980, Richmond called then-Massachusetts commissioner of corrections William T. Hogan to ask for a review of the classification decision that resulted in Randolph being moved to Walpole State Prison, a maximum security facility, according to interviews Hogan has given to The New York Times and The Boston Globe.

According to a May, 1980, Massachusetts document, Randolph was in "protective custody" in Walpole, one of the toughest institutions in the state. He was there, the document says, because of "drug debts incurred while at Norfolk," another facility in the Massachusetts corrections system.

Hogan last month recalled to an interviewer from The Boston Globe that "my recollection is the essence of the Richmond call was he knew this person and was asking me to review the classification that was made by the corrections department board."

Hogan did not return calls from The Washington Post.

Days after the Richmond-requested review had taken place, the correction board reclassified Randolph and voted 4-0 to send him back to Warwick Prison Camp, the medium security facility. The Warwick classification committee, however, took the unusual step of objecting to the transfer, calling Randolph "shaky," according to a Massachusetts corrections document and "rated as a potential escapee by many staff members."

The Massachusetts state classifications board thereafter sent Randolph back to the Brook House, the halfway house that had even less security than Warwick.

Shortly after he arrived at Brook House, however, Randolph was found to have taken drugs and he was scheduled for return to Walpole Prison.

Though he was due for a parole review in November, 1980, Randolph's new association with drugs would have made a new parole difficult, according to an official involved in the parole process.

On July 22, 1980, he dived through a window in the third-floor office of the director of Brook House while awaiting for corrections officials to take him back to Walpole. Luckily for Randolph, according to a knowledgeable official, his fall was broken by some tree branches and he escaped without serious injury.

Randolph's subsequent movements are unknown until January, 1981, when he went on the House payroll as a clerical assistant to the Doorkeeper of the House.