A 22-year-old Reston man, one of at least three suspects police have implicated in a series of rapes in Fairfax County, was found guilty yesterday of raping a 31-year-old Vietnamese woman, and of robbery and kidnaping in the incident.

The jury that convicted Raphael J. Boyd recommended a life prison term for rape and an additional 30 years for kidnaping and robbery in connection with the incident. Judge William G. Plummer will sentence Boyd on July 1.

Boyd faces trial later this month on charges of raping a 53-year-old woman in her Reston house. He also will be tried next week on two robbery charges in unrelated cases.

The two-day trial, interrupted briefly Monday by a last-minute search to find a Vietnamese interpreter to assist the victim in testifying, was the first of three trials involving suspects in a series of rapes that had occurred in Reston and other Fairfax County communities since last summer.

The rape for which Boyd was convicted yesterday occurred Jan. 10 outside an apartment building in Falls Church. The woman testified that her assailant grabbed her, gagged her and tied her hands, beat her, then dragged her to her car and raped her. She said the beatings and rape took place over a two-hour period.

The woman, who recounted details of the event with the occasional aid of the interpreter, stumbled several times over the word "rape." Finally, in response to prosecutor R. Dean Kidwell's questions, she spelled out the word.

Although the woman could not identify Boyd as her assailant, police testified his fingerprints were found inside the car where the rape occurred. Police also testified that Boyd confessed to the rape after he was arrested on another charge March 30.

Boyd took the stand and denied confessing. He said he was working his regular shift as a security guard for a Tysons Corner business at the time of the assault.

The case has highlighted aspects of one of the police department's most intensive and controversial rape investigations in recent years. During the most intensive period of investigation last November, police officers randomly stopped black men matching general descriptions of the rapist and asked them to voluntarily submit their fingerprints. Boyd was one of the men they stopped.

Because of the fingerprint check, he was later charged with two rapes, according to Kidwell. Boyd was questioned by police on March 30 after an officer noticed him running across a Reston golf course, wearing clothes similar to those worn by a man who committed a robbery several days earlier. Police checked Boyd's name through their files and eventually connected the fingerprints found in a rape victim's car to those on Boyd's card in police files. He was arrested later that day on the rape charge.

Boyd accused police of framing him by putting his fingerprints in the victim's car. Kidwell asked Boyd on the stand if it seemed to him that the fingerprints appeared in the car "by magic."

"It looks that way," Boyd said.