Fairfax County police, charged with alleged brutality during a melee in March at a Rte. 1 night club, were cleared of any wrongdoing in a police internal affairs investigation made public Friday.

"The officers acted properly under the circumstances," said Police Chief Col. Richard A. King of the incident at the One South Restaurant in which six people were arrested and several struck with nightsticks.

A couple involved in the March 18 fracas said yesterday that the police investigation was a "cover up" and that they have retained lawyers who plan to file suit against the county.

Linda DeMar, 21, of Alexandria, and her husband Steven, 20, who was convicted of assult and battery in connection with the incident, said they were sitting at a table in the bar when a policeman approached Steven and began hitting him with his nightstick.

Other witnesses at the club said that police seemed to be hitting patrons who looked both surprised by and afraid of the poilcemen.

King said in a press release that the use of batons by the policemen involved was warranted because of resistance by "an exceptionally strong individual" and the possibility of a "more dangerous situation developing."

A man who "violently resisted arrest" and kicked out the window of a police car was subdued by police using batons, Jing said. Police also struck other patrons who "interfered with the arrests" and "approached the officers in a menacing manner," he said.

Two policemen from the Groveton district station, Ernest L. Jones and William Petracca, who witnesses alleged acted wildly in arresting patrons, were among those cleared in the investigation.

Last week a federal grand jury began an investigation into allegation that three Fairfax Couty policemen needlessly beat a 16-year-old youth they were arresting at a Franconia roller rink in January. The grand jury is looking into both the conduct of the officers involved and the action of the police trial board that determined the three policemen acted properly.