The jury sat cross-legged, sipping beer and smoking cigarettes. The verdict unfolded in the laughter spilling over like stiff booze in a dark bar.

A woman in a white suit sitting on the edge of her chair at the back of the room kicked up her heels and cackled her judgment:

"He's funny," she said, doubling over.

For assistant Fairfax County prosecutor Bob Battle, it was another night in the unforgiving court of professional entertainment.

For three years, Battle has lived a Batman-like existence, prosecuting by day and executing his comedy routine by night at local clubs, cafes and bar associations -- slipping about on the comedy circuit, then back to court in the morning.

On Friday, the 31-year-old Battle ended his dual roles, retiring as an assistant commonwealth's attorney to become a full-time comedian.

As a prosecutor, Battle wore a look of suits, wire-rim glasses and seriousness. As a comedian Thursday night at Tysons Comedy Corner on Route 7, Battle made his case in a Goofy T-shirt and sneakers -- much of it humor with a legal spin.

His thin lips pursed, his crop of vanilla-colored hair tinged with red flopping about, Battle relayed his Top Five list from every prosecutor's nightmare: traffic court.

A cop pulls over a driver: "Can I see your license?"

The driver: "Sure, hold my beer."

The cop: "I'm writing you a ticket for speeding."

The driver: "Make it quick, I'm in a hurry."

The cop: "What took you so long to pull over?"

The driver: "A year ago my wife ran away with a cop and I thought you might be trying to return her."

Court provides some of his best material in the act, which includes impressions of Elvis and Michael Jackson greeting a gang in a New York subway.

When Battle, introduced as a prosecutor, climbed onstage Thursday night his title was greeted with hisses. The audience, which at times has included former defendants, was not sure what to expect.

"The fact that he's a prosecutor doing comedy makes them skeptical in the beginning," said Ron Maranian, owner of Tysons Comedy Corner, who spotted Battle a few years ago at a local club. "But in a couple of minutes, that fear or hesitancy dissolves and everybody is forgetting their problems, and that's the testimonial to comedy."

A few months ago, Battle decided to quit prosecuting and follow his calling. "People like comedians," he said. "People hate lawyers."

Last year, he competed in D.C.'s funniest lawyer contest and was a finalist in a local comedy competition. As a safety net, he said, he can always practice law on the side if the money gets low.

"He's a popular guy," said Tricia Sweeney, a New York agent who recruited Battle for an audition for a commercial. "He uses what's really happening, people getting busted for drunk driving and what they tell the judge or the cop. I think when he leaves and he's able to concentrate on that, he'll do very well."

Battle, who was bitten by the comedy bug in college, grew up in Alexandria, where his father was an FBI agent. At the University of Notre Dame, he hit the stage for the first time at a senior roast and had to wait minutes for the laughter to stop. At William and Mary law school, which he calls the school of Fred and Wilma, he participated in a student show, Libel Night.

Battle said his career as a comic has helped soften the stereotype some defense lawyers and defendants have of prosecutors. "It takes me out of the image of the prosecutor as a Nazi who has no sense of humor and places himself on a pedestal.

"I respect the defense attorney," he said. "Some guy might come up and ask for the moon. In general, I'm pretty easygoing and approachable. At least I hear them out and then I say no."

Battle said he hopes his days as a lawyer are limited. "I just signed a big contract with cable television," he said proudly onstage.

"Yeah, $40 a month plus free installation."