A D.C. police trial board recommended the firing of a police officer who was convicted in D.C. Superior Court of beating a prisoner being held at a police stationhouse on a disorderly conducted charge in April 1979.

The three-man trial board recommended on Feb. 5 that Tommy C. Musgrove, already sentenced to a year in prison, be removed from the force because of the conviction.

Musgrove, 26, of 12603 Lampton La., Oxon Hill, was found guilty last spring of simple assault on Michael Morris, 22, of 404 Hensdale Ct., Silver Spring. Musgrove is on bond pending an appeal of the conviction.

According to court testimony, Morris was arrested for disorderly conduct outside the Trailways bus station at 12th Street and New York Avenue NW and was taken to the 1st District substation cellblock in Southeast Washington.

Witnesses said Musgrove entered the cellblock and assaulted Morris with a blackjack after Morris had spat on him and refused to give his Social Security number.

Musgrove acknowledged that he struck Morris "to subdue him" after the spitting incident, but denied he beat Morris with a blackjack.

The trial board, by a 2-to-1 vote, found Musgrove not guilty of using excessive force against Morris but nevertheless recommended his dismissal because of the Superior Court assault conviction.

Deputy Chief Rodwell Catoe, in a dissenting opinion, said the failure of the board to find Musgrove guilty of excessive force is "inconsistent" with the board's acceptance of the guilty conviction.

Catoe asked Police Chief Burtell M. Jefferson to schedule another hearing for Musgrove.

Meanwhile, Catoe yesterday removed himself from a related trial board that has been convened to decide whether Sgt. Freddie Moss lied when he told police investigators that Morris was injured in the print room and not in the cellblock of the stationhouse.