When David Mavins was accused of shoplifting recently in Fairfax County, the black Anacostia resident found himself thrust into an unfamiliar world of justice in Northern Virginia: arrested, defended, tried, convicted and sentenced by whites.

Even if, as some contend, the Fairfax court system is color-blind, Mavins, 19, an 11th grade student at Anacostia High School who doesn't say much to strangers, felt the experience was intimidating. "It's my first time out here, but never again. I don't like it. There are too many whites and they're prejudiced. They don't want blacks out there shopping. They want whites because they can trust them," he said.

Last week, after appearing in a Fairfax court and receiving a six-month suspended sentence, Mavins boarded the bus for the two-hour ride home to the District. "From now on I'll stay in D.C. and shop," he said. "People here in Fairfax are a whole lot different."

County officials say they do not have exact figures, but those familiar with Fairfax cases largely agree that a sizeable number of low-income, black District residents are charged each year, especially with shoplifting.

"A lot of felony shoplifters are from D.C.," said Fairfax General District Court Judge F. Bruce Bach. "You have Bloomingdale's and an awful lot of nice stores to choose from if you are going to steal."

In Maryland, Chief Circuit Court Judge Ernest A. Loveless said the same phenomenon exists in suburban Prince George's County.

Fairfax County's 13-member prosecution staff has one black lawyer, Marcus D. Williams, who said he sometimes wonders whether the county's "all-white and often middle-class" juries "resent me because I'm black." The county's 639-member bar association includes one black lawyer. There are no black Fairfax judges and black jurors are rare.

"You know when you walk into the Fairfax courts, the prosecutor is going to be white, the judge is going to be white," said black attorney John L. Crump, director of the Washingtonbased 6,500-member National Bar Association.

"A certain feeling comes over you.Well, hell, it is one of fear, fear of the unknown That, at least, is what the black defendant feels... The individual is in a surrounding that is totally unfamiliar."

Transportation ordeals and wary bail bondsmen can add to a D.C. defendant's headaches, according to lawyers familiar with the courts. David Mavins showed up two hours late for his own trial after missing a series of buses from the District.

Yet Deputy Commonwealth's Attorney Steven A. Merril of Fairfax denies that the county courts are stacked against black defendants.

"It certainly is a fact that this county is 90 percent white, and that includes the judicial system. But our juries are very knowledgeable and sophisticated here in Fairfax. We don't have undereducated, countrytype juries," Merril said.

Bobby B. Stafford, a black Alexandria lawyer, agrees it can be an "advantage" to be tried in Fairfax because "you have smart people on your jury" with broader experience than District jurors.

Yet long before the jury stage, many District families face frustration in trying to arrange for bond to free a relative from Fairfax jail.

Bondsmen operating near the Fairfax courthouse said they are reluctant to bond out-of-state defendants who do not own property in Virginia, and who may not return to stand trial. "Nine out of 10 of them (District defendants) don't show up," said Ken Connally of Payne Bonding Co.

Said another bondsman, B. Rasnick of Roseberry Bonding Co.: "If you bond someone from D.C. on $125 bond and then try to go pick them up (for failure to appear in court), you are taking a chance of getting killed."

So when a Fairfax judge recently set David Mavins' bail at $500, his mother, Barbara Ann Mavins, a clerk, could not persuade any local bondsman to put up funds for her eldest son's release.

"If he was from Arlington, or local, it would have cost him $50," said his lawyer, Peter D. Greenspun, as he waited the other day for Mavins to show up for trial. Eventually, Greenspun persuaded a Fairfax judge to accept a reduced cash bond of $250, paid for by Mavins' mother, and after two days in jail Mavins was released.

Another defendant, Yvonne Harris, 21, of Northeast Washington, charged with shoplifting at Springfield Mall, sat in Fairfax jail for five days before bail could be arranged.

A succession of bondsmen refused to put up her $1,000 bond. Finally, a Fairfax judge, faced with keeping her in the already overcrowded jail until her Jan. 31 trial, reduced her bail to $100 and she was set free.

Even if a bondsman is willing to cooperate, some Farfiax judges are not easily persuaded to release out-of-state residents from custody. According to local lawyers, some judges, irked by the District's refusal to extradite defendants who fail to return for trial, are reluctant to let D.C. defendants go.

"The worst thing you can say to General (District Court) Judge J. Mason Grove is, this man is from the District of Columbia," one local lawyer remarked recently.

"The commonwealth's opinion is that once they go across the river, they are not going to come back any more," said another lawyer, Myron Teluk. In other, smaller ways, it makes a difference where defendants come from. The Fairfax courts are about to embark on an innovative pretrial program that would allow certain first offenders to perform social work rather than stand trial.

The program, according to Chief General District Court Judge Robert Hurst, is meant especially for accused shoplifters, yet it will be limited strictly to defendants from Virginia.

"Because," said Hurst, "if the D.C. resident decides at some point he doesn't want to participate, there is no way we can get him back."