After 8 1/2 hours of deliberation, a Fairfax County Circuit Court jury was unable to reach a verdict yesterday in a case charging an Alexandria fire captain with four felony counts of indecent exposure.

Randall H. Long, 37, of the 5900 block of Vernons Oak Court in Fairfax, was charged with indecent exposure with lascivious intent to minors in two incidents involving two 11-year-old children walking to school together. The penalty on each charge is a maximum of five years in prison.

"The state put on its best case and all its evidence was not enough to convict Mr. Long," said defense attorney Thomas P. Dugan. "We see that as a vindication."

Assistant Commonwealth's Attorney Raymond L. Brownelle, who said yesterday that he probably will retry the case, maintained during the two-day trial that Long had honked his horn at the two children on both occasions and then opened the car door and exposed himself.

"It's perverted. No question about it, it's perverted," Brownelle told the jury during closing arguments.

The two children, who are both 12 years old now, took the stand.

Dugan maintained that it was a case of mistaken identity and that, when the first incident occurred, his client was on his way to National Airport to pick up his brother.

During the second incident, he argued, Long was home after being relieved for the day at 7:30 a.m. from his job at the fire department, where he has worked for 13 years.

In addition to the felony charges, the jury could have found Long guilty on two counts of the lesser charge of indecent exposure, on which the maximum penalty is 12 months and a $1,000 fine on each charge.

Long also faces a single misdemeanor charge of indecent exposure in an incident at George Mason University. He was scheduled for a court appearance on that charge yesterday, but the case was continued.