Melvin Kevin Johnson, whose younger brother was convicted of a single count of manslaughter in connection with the shooting deaths of two Prince George's County police officers, was sentenced to a six-month jail term yesterday for robbing a laundry coin box.

The robbery, which netted the 19 year-old Johnson $29.75 in quarters, triggered the arrest of the two brothers a few hours later as they drove to a movie.

It was after the pair had been arrested and taken to the Hyattsville police station that Terrence G. Johnson, now 16, grabbed a gun from officer Albert M. Claggett IV and shot and killed Claggett and officer James Brian Swart.

Melvin Johnson pleaded guilty in connection with the break-in at the laundromat, in which Terrence played no part. In return, several other related counts against him were dropped.

Prince George's County Ciruit Court Judge Samuel W. H. Meloy could have sentenced Johnson to a maximum term of 18 months in jail.A presentence investigation by the Department of Parole and Probation had recommended that the 19-year-old be placed on probation because he had no criminal or juvenile record.

Prosecutor Stephen Orenstein made no specific recommendation to the judge but later said, "we don't fell this was an inappropriate sentence."

Johnson's attorney, LeonardMcCants also said he was "very disappointed that the judge did not choose probation."

Johnson was taken into custody by sheriff's deputies immediately after the sentence. His brother, who will be sentenced on convictions of manslaughter and illegal use of a handgun on May 3, currently is in the Calvert County jail. He faces a sentence of up to 25 years.