In a bizarre flare-up, Republican Fairfax County Supervisor Elaine N. McConnell has asked the U.S. attorney to investigate whether Democratic Board Chairman Audrey Moore illegally disrupted county contract procedures in an attempt to silence a critic.

However, U.S. Attorney Henry E. Hudson told McConnell yesterday that the allegation, even if true, does not come under federal jurisdiction. McConnell said she will next ask Commonwealth's Attorney Robert F. Horan to investigate. Horan, a Democrat, is out of town and could not be reached for comment.

McConnell, a longtime political antagonist of Moore's, said she asked for the investigation after hearing that Moore had threatened to deny county contracts to the consulting and accounting firm KPGM Peat Marwick because the head of its Northern Virginia office, Gary R. Hevey, has been a vocal critic of the board.

Hevey is also the chairman of the Fairfax County Chamber of Commerce and has played a leading role in attacking the board's decisions to raise business taxes and curtail development.

Hal I. Steinberg, who oversees county contracts for Peat Marwick, said, "From my understanding, there was no threat made like that."

Hevey, through a chamber spokeswoman, declined to comment.

Moore, through a spokesman, said the charge of contract meddling was "not true" and "a deliberate misrepresentation of the facts."

And County Executive J. Hamilton Lambert noted that "the chairman of the board has neither the right to terminate or institute contractual relationships."

The situation nonetheless represents a new low in relations between Moore and the business community, who have had rocky relations for years, and another public struggle between Moore and McConnell.

Asked to explain the basis of the allegation, McConnell said, "A reporter told me." She declined to identify the reporter or say whether she has talked to Hevey. Sources said McConnell has discussed the matter with Hevey.

"I'm asking for an investigation of a public official threatening a business," McConnell said. "I confirmed this with a reliable source . . . . I cannot, under my oath of office, ignore an allegation like this."

Sources trace the controversy to a conversation Moore had with one of Hevey's Peat Marwick bosses at a social gathering about a month ago. The sources said Moore upbraided Hevey for critical remarks he has made during his term as chamber chairman, which ends this month. Peat Marwick has a variety of contracts with the county, including a three-year, $514,000 contract to audit the county's books.

Moore said on Wednesday that she could not recall a specific conversation she had ever had with anyone from Peat Marwick about Hevey.

But she said she was "outraged" at the "blatant lies" she said Hevey had told in testimony before the General Assembly this year and in chamber mailings.

Moore said the comments dealt with whether the county had made a commitment never to downzone land in the Route 28 special tax district, where landowners agreed to pay a special tax for road improvements.

"Anybody who had anything to do with Gary and the chamber and that subject came up, I would have expressed my indignation," Moore said.

The legislature overturned the county's downzoning in the Route 28 corridor, near Dulles International Airport, principally because state lawmakers believed that in exchange for agreeing to tax themselves, landowners should not have their development rights reduced.

County developers and business leaders appearing in Richmond at times suggested that the county had made an official commitment and legislators eventually concluded that the Route 28 downzoning violated an "understanding."

"I think that when Mr. Hevey, who is a leader of the business community, put out in writing and said in public that Fairfax welshed on a commitment, it was a serious charge and it was false and . . . I think he should be held accountable for his actions," Moore said. "Does Mr. Hevey think that it's okay to do these things as chairman of the chamber, but that it's supposed to be an okay practice with his company?"

Judith Forehand, president of the chamber, said that Hevey "has had the total support of the chamber representing the business community this year.

"The chamber unequivocally supports its position regarding the Route 28 corridor and the rights of landowners, and it's unfortunate that Mrs. Moore cannot see the business community's perspective."

Staff writer Robert F. Howe contributed to this report.