A D.C. police captain who earlier this year was involved in a shootout with a female police detective was found guilty yesterday of two instances of official misconduct by a police trial board that recommended he be demoted to lieutenant.

If the board's recommendation is accepted by Chief Maurice T. Turner, who is scheduled to consider the case today, it would be the first time in 25 years that a high department official has lost his rank.

The three-member trial board, investigating a March 14 shooting involving Capt. Charles R. Bacon and detective Esther H. Dimery near a house they shared in Oxon Hill, found Bacon guilty of firing his service revolver unnecessarily and of "conduct prejudicial to the good order and reputation of the police department."

Bacon, a 13-year department veteran formerly assigned to the administrative services division at D.C. police headquarters, returned to active duty in July. Since then he has been assigned as a supervisory captain of the 5th District in Northeast Washington.

Shortly after the shooting incident Bacon was placed on sick leave and spent 28 days in a local alcohol-treatment facility.

The trial board deliberations were marked by a parade of high-ranking police officials who testified on Bacon's behalf.

Initially, Bacon was charged by Prince George's County police with assault with intent to commit murder as a result of four shots he allegedly fired at Dimery during a domestic dispute. Those charges later were dropped when Dimery refused to testify against him.

At the trial board hearings, Bacon testified that he had been drinking heavily that evening at the office and on the way home. An argument with Dimery ensued, he testified, when both accused each other of infidelity.

Dimery also fired a shot during the incident. She received an official reprimand and returned to duty.