A D.C. Superior Court jury yesterday convicted two brothers of first degree murder in the brutal slaying last year of Clifford T. Talley, a 22-year-old postal union employe.

Talley was bludgeoned and shot to death in an alley off the 300 block of Elm Street NW last July. The killing gained particular notoriety after Talley's brother, Charles L. Talley, who was home on military leave for the funeral, was shot to death in the same block in an apparently unrelated slaying.

Christopher McAdoo and Duane Wilson yesterday were convicted of first degree murder and carrying a pistol without a license in the slaying of Clifford Talley.

According to court testimony, a dispute between Clifford Talley and Wilson began last July when Wilson allegedly beat a cousin of Talley. The cousin, 28-year-old Sharon Epps, told the jury that Wilson had beaten her after a dispute over the cost of some of the drug PCP that she had sold him. She said the drugs were worth $15, and Wilson would only pay her $12.

On July 6, Talley confronted Wilson and beat him, according to court testimony. Wilson returned later that night with his brother and confronted Talley.

According to defense attorneys, Wilson and McAdoo, who maintained their innocence, had come to make peace with Talley. But another of Talley's cousins, 32-year-old Sandra Evans, fought back tears as she told the jury she watched from a short distance as Wilson beat Talley to the ground with a table leg, and McAdoo leaned to within inches of the victim and fired a bullet through his skull.

McAdoo testified that Talley fled down an alley and was shot by an unknown assailant.

McAdoo and Wilson face minimum sentences of 21 years in prison. Judge Fred L. McIntyre set sentencing for May 12.

After the verdict Kathryn Jackson, a city employe and sister of the two slain men, said, "I'm happy that we could see justice done."

Another man, 20-year-old Gerald Smith of 127 35th St. NE, has been charged with homicide in the unrelated slaying of Charles Talley.