A defense attorney for a 24-year-old man accused of a random slaying that called attention last year to serious drug problems at a Gaithersburg housing project asserted yesterday that the case against his client was a "tattered . . . rag woven together by the rotten thread of a jailhouse informant."

Joseph P. Suntum made the statement during opening arguments in the first-degree murder trial of Chester Allen Mowell, who is accused of the Oct. 27 shooting of Andre E. Prather outside the Amity Gardens Apartments in Gaithersburg.

Assistant State's Attorney David A. Boynton, who is prosecuting the case, said he would present no direct evidence linking Mowell to the crime, but that Mowell had described the shooting in detail to an inmate at the Montgomery County Detention Center.

Boynton said there was no other way for the inmate to get the information except from Mowell. But Suntum asserted that the courtroom would "reek from the stench of the relationship" between Boynton and the inmate.

After implicating Mowell, Suntum said, the inmate was transferred from the jail to a work-release center from which he promptly escaped. After he was recaptured, Suntum said, Boynton testified on the inmate's behalf during a District Court hearing.

Prather, 22, of Germantown was killed by a gunman who raced by the project in a speeding car and fired several shots into a crowd standing in the parking lot.

More than 100 people were outside at the time Prather was hit in the head by one of the bullets, but all said they could not identify the assailant or the make of the car.

The shooting was the third that month in the lot of the federally assisted, low-income housing project, which police and residents described as a "stop and cop" spot where drugs could be bought any time.

Boynton said Mowell drove to the lot the night before the shooting with a friend to buy drugs, but got involved in an altercation with a man.

Mowell brandished a pistol, which later turned out to be a broken pellet gun, and sped from the scene with his automobile lights out. A nearby police officer pulled him over and arrested him for drunk driving, Boynton said.

Mowell, however, escaped from the police cruiser and was not apprehended for 36 hours. Prosecuting and defense attorneys offered widely differing versions of his whereabouts during that time.

Boynton said Mowell told the inmate that he returned to the project the following night in the speeding car to take revenge on the person who "ripped him off."

But Suntum said witnesses would testify that Mowell was nowhere near the apartment complex at the time of the shooting.