A Fairfax County Circuit Court jury found one of the county's two remaining adult bookstores guilty yesterday of renting an obscene film and set punishment at a $1,000 fine.

The jury also acquitted the store, Croatan Books, Inc. at 8653 Richmond Hwy., of two other counts of renting obscene films, overturning an earlier conviction on those charges by a General District Court judge.

Circuit Judge Thomas J. Middleton scheduled sentencing for Sept. 22. He could decrease but not increase the fine set by the jury.

Fairfax Commonwealth's Attorney Robert F. Hornan Jr. has campaigned for two years to rid the county of adult book stores and movies by charging them with violating obscenity laws.

The two adult bookstores in the county are one less than a year ago. Besides Croatan Books, the county has Educational Books Inc. at 9158 Richmond Hwy. near Fort Belvoir.

To convict an individual or corporation under Virginia's obscenity statute, prosecutors must prove that material violates a particular community's standards using guidelines set by the U.S. Supreme Court.Taking the material as a whole, it must appeal to prurient interests, be patently offensive to the community and lack literary, artistic, political or scientific value to be deemed obscene.

In the Croatan Books' hearing, two police investigators testified that they had seized the three nine-minute films from 25-cent peep shows in the bookstore in January.

The films, which were viewed by the jury, show a wide variety of sexual activities.

Stanley H. Dietz, an attorney for Croatan Books, argued that the films were not obscene but showed "normal things that people do."

Croatan Books was found guilty last August on eight counts of renting obscene films and the corporation was sentenced the maximum fine of $1,000 on each charge.