Board of County Supervisors Chairman Sean T. Connaughton (R) and Sheriff E. Lee Stoffregen III (D), rivals and two of Prince William's fiercest political warriors, will each face internal party competition this year.

Each faces a countywide June 10 primary in his respective party, according to campaign forms filed by Friday's deadline.

Last week, Democrat John Collier, a 28-year veteran of Prince William police, filed to take on Stoffregen in the Democratic primary. In November, the winner of that contest will face a Republican, Col. Glendell Hill. Connaughton is Stoffregen's leading opponent on the board and has rallied Republican support behind Hill.

On Friday, Connaughton learned he will have a Republican opponent: Larry D. Williams Sr., a former D.C. homicide detective and former Prince William deputy sheriff who is close to Stoffregen and other prominent Democrats.

Friday was the last day to file under a political party. Gainesville Supervisor Edgar S. Wilbourn III, who was facing a Republican primary opponent, allowed the deadline to pass without filing, which leaves Republican John T. Stirrup unopposed for the party's nomination. Wilbourn could still decide to run as an independent, which would guarantee him a spot on the November ballot. Independents can file as late as June 10.

There will be five other primaries and conventions for seats on the Board of County Supervisors. Supervisor Hilda M. Barg will face Democrat John Thompson in a primary in the Woodbridge magisterial district, said George Delimba, Prince William Democratic chairman. And incumbent Mary K. Hill will face Martin E. Nohe in a Coles District Republican primary.

In the Occoquan District seat vacated by Ruth T. Griggs (R), John S. Gray and Keith A. Scarborough will seek the Democratic nod and Frank E. Bolton, Corey Alan Stewart and Stephen R. Wassenberg will face each other in a Republican primary.

In the open race for the Brentsville District seat vacated by Loring B. "Ben" Thompson (R), W.S. "Wally" Covington III will face Richard D. Jankowski in a Republican convention May 10.

"I'm surprised the incumbents don't share my enthusiasm for primaries, because I think it's a good idea that gets names and issues out in front of the voters earlier in the year," Delimba said.

His counterpart, Bruce Baxter, said he is confident Republicans will do well this year. "The more the merrier," Baxter said of the competition.

But Baxter said he was disappointed Wilbourn didn't file.

"He told me point-blank he wanted a primary," the Republican chairman said. "My sense is that he felt he was going to get creamed in the primary."

Political leaders said the most intriguing last-minute development was the announcement by Williams that he would challenge Connaughton.

Williams said he was an "average guy" who is running to lower taxes and promote cooperation between emergency first-responders in an era of terrorist threats. He said he was especially upset over the actions of supervisors who crow about lowering the tax rate while property assessments increase, pushing tax bills up.

"That's an easy way to get out of it, lie and deny," Williams said.

Connaughton said he sees Williams's candidacy as retaliation.

"He is a deputy sheriff, his campaign manager is the sheriff's closest friend, and the vice chairman of the Democratic party notarized his petitions. Do I need to draw any clearer a picture?" Connaughton said.

He said he was "extremely affronted" that Stoffregen would try to affect internal Republican politics.

William denied he was anyone's pawn.

"The last I checked we're all Americans," he said. "There's no hidden agenda. I do know the sheriff and other Democrats in the county, but I'm not going to be a tool for them to hurt -- what's-his-name -- Sean Connaughton."