A D.C. Superior Court jury yesterday convicted a 17-year-old Northwest Washington youth of second degree murder in the May 11, 1982, beating death of a 70-year-old retired builder who had employed the youth as a gardener.

The youth, Charles T. Barnes, of 1004 Otis Pl. NW, was also convicted of burglary and petty larceny in the death of Harry E. Gorin of 3120 Appleton St. NW. He faces a maximum sentence of from 30 years to life in prison.

D.C. Superior Court Chief Judge H. Carl Moultrie I said he would sentence Barnes on Sept. 20.

Assistant U.S. Attorney William D. Nussbaum told the jury during the week-long trial that Barnes, who had worked for Gorin for about 18 months before the incident, killed Gorin with an ax after Gorin found him in the home stealing household items.

In a search of Barnes' home, Nussbaum said, police found various items belonging to Gorin, including a radio, camera equipment and clothing.

Gorin's brother, Louis, testified that before the day of the killing, Harry Gorin suspected Barnes was stealing from the home. Louis Gorin said he and his brother devised a plan in which Louis Gorin, who also employed the youth, called Barnes to work on his yard, adjacent to his brother's.

According to the plan, Harry Gorin stayed at home to see if Barnes entered his house.

Louis Gorin testified that, on the day of the killing, Harry Gorin called and said he had confronted Barnes inside his house and that Barnes promised to return the items and a small amount of money. Louis Gorin said his brother told him that he had promised Barnes he would not tell Barnes' mother or the police if the items were returned. The telephone conversation ended when Barnes appeared as scheduled at Louis Gorin's home to work.

Later, Nussbaum argued, Barnes returned to Harry Gorin's home to kill him.

Barnes, meanwhile, testified that he went to Harry Gorin's home to borrow a lawnmower, that Gorin attacked him and that Barnes killed him in self-defense.

Nussbaum argued, however, that it was unlikely that the elderly Gorin, who suffered from arthritis in both knees and a heart condition, attacked Barnes.

After the verdict, Louis Gorin said in an interview that Barnes was a hard worker and a "good kid."

"My brother was so good to him," Gorin said. "He used to make lunch for himself and fix something for Timothy (Barnes) and they would sit and have lunch together. Maybe he Barnes was afraid he Harry Gorin would tell" police despite his promise not to do so, Gorin said.

Harry Gorin's wife Selma, found his body in the family room of the bilevel brick house. According to medical testimony at the trial, Gorin was killed by repeated blows to the head, including two that were struck after Gorin's head was on the floor.