An alleged drug-ring lieutenant was convicted of first-degree murder yesterday in the deaths of two men, including one who was to testify against him before a grand jury investigating the first victim's death.

Tarik Coefield, 20, was found guilty by a D.C. Superior Court jury after testimony that he arranged the killing of the second victim, 18-year-old Marcus Herring, when Herring refused to accept a bribe to cancel his appearance before the grand jury.

According to the testimony, Herring was expected to tell the grand jury investigating the Feb. 27, 1989, death of Eddie Martin, 19, that he saw Coefield shoot Martin several times in a dispute over how drug money was being collected. Coefield was a lieutenant in a drug organization based on Newton Street NW, prosecutors said.

At the time of the first slaying, Coefield was awaiting trial on a separate charge of carrying a dangerous weapon, prosecutor Paul Howes told the jury. After his arrest in Martin's slaying, Coefield was released on $25,000 bond. A month later, he ordered Herring's death, prosecutors said.

The night he died, Herring had agreed to meet a friend in a parking lot in the 3400 block of 14th Street NW, witnesses said.

Once there, they said, Herring was offered $3,000 to $5,000 to cancel his grand jury appearance. When it became clear he would not, Coefield signaled another man, Kenneth Forgy, to shoot Herring, witnesses said. Forgy is scheduled to be tried Feb. 14 for his alleged role in the slaying.

Coefield also was convicted of several other counts, including obstruction of justice and carrying a pistol without a license, and is scheduled to be sentenced March 26. He faces a mandatory prison term of at least 20 years.