The word had been passed among the deputies that if the Fairfax County Board of Supervisors angered the sheriff and goaded him into walking out of the board room last week, then the deputies would walk out, too.

But James D. Swinson, the embattled sheriff of Fairfax County who says that he "can take and dish it out," did not get mad. Swinson, with his country-fried humor and a claim that he runs the best jail in Virginia, did not walk out of the board room until after he spent more than two hours demonstrating that he was more than a match for the board.

When he was good and ready, Swinson, whose department has been under investigation for seven months for alleged misure of jail inmates, said he would have "no further statement" on alleged wrongdoing in his jail.

"I am finished, period, thank you," the sheriff said. He walked out as his deputies, who'd packed the board room, gave him a standing ovation and marched outside behind him.

The sheriff would have left the board room unscathed had not one of his defenders, Supervisor James P. Shacochis (R-Dranesville), asked just before the sheriff's grand exist that Commonwealth's Attorney Robert F. Horan come forward and speak out on what the investigation of Swinson has uncovered.

Shacochis, who for weeks has been saying that Horan's investigation of Swinson has political understones, called on Horan in an effort to clear up lingering doubts in the county about the sheriff's integrity. The effort, however, backfired.

Horan, a Democrat, said his investigation of the sheriff, a Republican, has found no evidence that Swinson commited a crime. But, in front of all nine supervisors, television cameras and the sheriff himself. Horan said he has uncovered a "widespread" pattern of inmate abuse from 1974 through 1976 on the part of high-ranking deputies in the county jail.

"I cannot believe," Horan said, referring to the pattern of inmate abuse the said he has uncovered, "that magically this type of activity ceased."

After Horan's statement, Swinson appeared less mirthful and less confident. The sheriff, who an hour earlier in the session had called himself a "tough old goat" who wanted to "let it all hang out," refused to comply with a request by Supervisor James M. Scott (D-Providence) that he issue a written order to his deputies, telling them to cooperate with Horan's investigation.

It was "too late" to do that, Swinson told Scott, because Horan had enough "stool pigeons running to him" and besides, "certain animosities have built up." Horan said he has been told by deputies that they are afraid to talk about illegal activities in the sheriff's department because they fear they'll be fired.

Swinson might have had a much tougher grilling from the board had not four supervisors, three Republicans and Democrat Joseph Alexander from Lee District, opposed the public questioning of the sheriff before it even began.

Alexander had called the inquiry an "inquisition," Shacochis said it was "political harassment," and Republican board chairman John F. Herrity, who is running for Northern Virginia's Eighth Congressional District seat, opposed questioning Swinson but refused to say why.

Marie B. Travesky (R-Springfield) declined the chance to question the sheriff about why he had not disciplined deputies who allegedly used jail inmates for their own private purposes. Instead she offered what she called a "little commercial" for Swinson.

She said she had spoken to top officials in the Virginia Department of Corrections and they told her that Swinson's jail was the envy of Virginia and that he was a fine administrator.

The supervisor who did try to grill Swinson, Alan H. Magazine (D-Mason), was nearly as unsuccessful in attacking the sheriff's integrity as Shacochis was in defending it.

Magazine spoke of unnamed deputies in the department who had told him the sheriff's son-in-law, Capt. Carl Peed, had been promoted three times in three years. Magazine, who admitted that Peed was considered a hardworking and capable deputy, could only ask Swinson if he thought hiring and promoting such a close relative was "good for the system."

Swinson said Fairfax County was "lucky" to have Peed, and that he had "no problems" with his son-in-law's success.

In the lobby of the Massey Building outside the board room after Swinson had walked out with his entourage of deputies, the sheriff complained that many of his problems have been brought on by newspapers that keep writing about Horan's investigation even though he says the investigation has come up with nothing against him.

More than a month ago the sheriff told Horan and the press to "put up or shut up," and now Swinson himself, with Horan's investigation continuing and the press continuing to write about it, has decided he is the one who will shut up.