Richard Lee Earman said yesterday that a pivotal reason he agreed to plead guilty to conspiring to murder an Arlington couple was prosecutor William S. Burroughs' agreement that "I could have my choice of any federal 'country club' prison I wanted."

In a wide-ranging two-hour interview, Earman, a former Northern Virginia real estate salesman, said Burroughs also agreed that he could take a week's vacation in the Bahamas before going to jail.

Burroughs, Arlington's commonwealth's attorney, confirmed yesterday that his agreement with Earman, currently free on a $2,000 bond, allows him to select his prison and to travel to the Bahamas. But Burroughs angrily defended the agreement, saying it was crucial to solving the 1977 double murder.

"This doesn't happen every day but it's not uncommon to make arrangements to protect witnesses who have cooperated with the state," the prosecutor said.

In the latest twist in a bizarre case, Earman, 36, agreed last week to cooperate with prosecutors and testify against Joseph N. Martin of Las Vegas, 28, who is accused of conspiring with Earman to murder the couple. Martin has declined to comment on the charge.

Two years ago, Burroughs accused both Earman and Martin of murder in the deaths of real estate agent Alan Foreman, 26, and his fiancee, Denna Shoemaker, 25. They were shot to death in the garage of Foreman's North Arlington home.

Earman was acquitted of murder charges during an eight-day trial that year at which the prosecutor dropped the charges against Martin. Burroughs' handling of the case has continued to provoke controversy in Northern Virginia and is expected to be an issue in Burroughs' reelection campaign this spring.

When asked about Earman's latest starements yesterday, Burroughs was clearly irritated. "The points you raise and the questions you ask are just so much bull - - - -," he told a reporter. "I want the media to stop wasting my time and start understanding this case."

Burroughs said yesterday that Earman faces a maximum of 10 years in prison for his plea to the conspiracy charge. "This is not an effort to get him into a quote country club prison.

"Do you really think 10 years of a man's life hinges on whether he's goint to go to the Bahamas or not?" Burroughs asked. "I agreed to continue his bond so that he could cooperate with us in the continuing investigation and get his affairs in order. Is it better that we don't get the coconspirators?"

Earman said, however, that he is "seriously considering" withdrawing or changing his guilty plea on March 26, the day he has agreed to be jailed. He is to leave today on a week-long vacation in the Bahamas.

"Let's get all this plea stuff out in the open," said Earman as he lunched on a chef's salad and a bloody mary in a fashionable Rosslyn restaurant. He said he was told through intermediaries that if he refused the deal Burroughs offered, Fairfax County authorities would arrest him on burglary charges and would deal harshly with his younger brother, David, currently in jail there on burglary and bad check charges.

As part of the plea bargaining Fair-fax and Arlington prosecutors agreed to drop various felony charges against him.

"If I was never threatened or pressured there would have been no deal," Earman said. "If I change my plea they have to start over and move the trial because with all the publicity I'd never get a fair trial around here."

His comments yesterday contradicted what he told Arlington Circuit Court Judge Charles S. Russell last week. Earman then said he had not been pressured or coerced into agreeing to the deal.

"In the course of this I've given so many different tales (to police and Burroughs)," Earman said. "But I've been around long enough so I know if you tell them things they want to hear, they just eat it up." Police and Burroughs say Earman told police several times that he was a party to the Foreman and Shoemaker shootngs.

Earman said he has been pondering his choice of prison. "I'll probably pick a coed place, like where Patty Hearst was. I'd rather go somewhere I can play tennis," said Earman, who has worked as a tennis instructor and wears a large diamond-studded gold ring in the shape of two tennis rackets.

Burroughs said that Earman could change his plea only with a judge's approval and "not without good reason, and there isn't one in this case."

"Lee is his own worst enemy," Burroughs roughs said. "If he'd just keep his mouth shut, he'd be okay."