A 29-year-old Northeast man pleaded guilty to involuntary manslaughter in D.C. Superior Court yesterday in a case in which another man was convicted and spent five years in prison.

Richard E. Harris, of 612 14th St. NE, appeared before Judge Paul R. Webber III and said that he is the one who fatally wounded Rodney Frazier on Nov. 2, 1974 after he attempted to steal drugs at gun point from Frazier's home at 1601 W St. SE. Frazier died two days after in the incident.

A short time afterward Bradford Brown, now 32, of 1842 Providence St. NE was arrested and charged with second-degree murder in Frazier's death. Brown testified at his trial that he was at a birthday party at the time of the slaying, but a jury convicted him, and he was sentenced by Judge Norma Johnson to 15 years to life in prison.

In June D.C. police uncovered additional evidence that indicated that Brown was not involved in the shootings. Brown was released from Lorton a month ago after news of the new evidence was presented in court by U.S. Attorney Carl S. Rauh.

Harris said in a brief statement in court yesterday that he went to Frazier's house with a revolver expecting to rob Frazier of drugs. But while he was inside the house, Harris said a dispute began and he rushed out.

Harris said he was running out of a door when the gun discharged, wounding Frazier in the abdomen. Harris said yesterday that he thought he had shot Frazier in the leg.

Since shortly after the shooting, Harris has been serving a jail term at Lorton Reformatory on a separate robbery charge and was not aware that Frazier had died of the wound, according to his court-appointed attorney John Treanor.

Brown was convicted on Nov. 28, 1975, after a government witness identified him from photographs and in a lineup as the man who had shot Frazier.

In testimony at Brown's trial, the witness said that the man who did the shooting that night had come to the door of the W Street house earlier and asked to see a man who lived there.

The man then left a name and telephone number on a slip of paper, which was later lost by police. The witness testified that moments later the man returned to the house, forced his way inside and pointed a gun at her. The shooting of Frazier occurred minutes later, she said.

Det. Robert J. Kanjian, assigned to the career criminal unit of Superior Court, and others in the unit, uncovered new evidence that cleared Brown while interviewing a defendant in an unrelated case on June 28, according to court sources. Details of the new evidence were not disclosed.