A D.C. Superior Court jury yesterday convicted 25-year-old Gregory Earl Williams of first-degree murder, armed robbery and assault in connection with the shooting death last February of an off-duty D.C. police officer during the holdup of a Georgia Avenue go-go club.

The jury of eight women and four men deliberated for one hour before 4 returning the verdict to Judge John F. Doyle, Government witnesses had tesified during the five-day trial that Williams told them he shot Officer Bernis Carr Jr., 34, because Carr reached for his service revolver and "tried to be a hero" during the robbery.

Assistant U.S. Attorney Harry R. Benner contended that the robbery was carried out by five young men but that Williams had fired two shots from a silver, 22-caliber revolver that struck Carr in the head and chest.

Carr, a 12-year veteran of the police force and father of two children, fired two shots from his service revolver before being killed according to government evidence. One shot lodged in the bar ceiling, and another struck one holdup man, the government said.

The incident occurred about 7.45 p.m. last Feb. 16 at Jimi's lounge at 4301 Georgia Ave. NW. Carr. two dancers and the bar manager were in the lounge having a drink at the time of the robbery and shooting according to the government's case.

Prior to William's trial, three men charged in connection with the shooting and holdup had pleaded guilty in Superior Court to second-degree murder and armed robbery. A fourth man pleaded guilty to first-degree murder while armed. Those four are awaiting sentencing and Williams is to be sentenced Nov. 17.

In addition to murder, Williams was convicted of the armed robbery of Carr and the bar manager and two counts of assault with intent to commit robbery while armed in connection with the dancers.

Williams faces a minimum sentence of 20 years in prison on the murder charge and could be sentenced to life in prison on each of the four additional convictions, the U.S. attorney's office said.

In a signed statement given to a police detective at the time of his arrest, Williams said he and the four men had cruised the Georgia Avenue NW neighborhood the night of the incident and talked about "raising a joint," according to testimony at the trial."It was a spur of the moment thing" when they decided Jimi's would be the target of the holdup, according to the statement.

No experience was offered during the trial in Williams defense. His attorney, Carrie L. Fair, challenged the credibility of the government's witnesses and questioned their ability to identify Williams as one of the robbers. She also argued that police used improper procedures to obtain the statement from Williams.