The District of Columbia government has agreed to pay $10,000 to a 23-year-old Northeast Washington man who was held in prison on an armed robbery conviction six months after another suspect confessed to the crime and said the convicted man was not involved.

Kevin M. Quander, 23, who had been serving a maximum 30-year sentence on the armed robbery charge, had filed a false imprisonment lawsuit in U.S. District Court here, alleging that city law enforcement officials failed to promptly investigate the suspect's admission. Judge Thomas A. Flannery, who was scheduled to begin a trial in the case Thursday, was notified yesterday that the city had agreed to settle the case out of court, according to Quander's lawyer, Joel DuBoff.

Quander was sentenced by a D.C. Superior Court judge in November 1977 to serve five to 30 years in prison after a jury found him guilty of the armed robbery. The victim in the case, a nurse, had positively identified Quander at a police lineup as the man who held a gun to her head during the holdup, DuBoff said.

In November 1978, after Quander had served a year of his sentence at Lorton Reformatory, another suspect, Rawleigh F. Fitzgerald Jr., 22, pleaded guilty to the same June 1977 robbery for which Quander was convicted. Fitzgerald, who was placed on probation under the terms of the Youth Corrections Act, told a Superior Court judge that he didn't know Quander and identified another man as his accomplice.

Quander, however, remained at Lorton until April 1979, when the government dismissed the indictment against him, after Quander had won the right to a new trial. A lie-detector test, administered a month earlier and prompted by Fitzgerald's guilty plea, showed conclusively that Quander was innocent of the crime, attorneys in the case agreed.

Washington police were never able to locate the man who Fitzgerald said was his accomplice and identified only as "Ricky Ricardo." According to court records, a search of official files, checks of aliases and a lead to a local poolroom failed to turn up any person who could be linked to the crime with Fitzgerald.

Quander, who lives with his grandmother at 717 Seventh St. NE, contended that he had gone straight home from his maintenance job at National Airport on the night of the June 1977 robbery on Constitution Avenue NE, according to DuBoff. Quander, who did not testify at his trial, is currently unemployed, DuBoff said.

Police showed the victim in the case an array of pictures of potential suspects in the case, including Quander, who had a previous conviction for assault with intent to rob, DuBoff said. The woman tentatively identified two suspects who might be the gunman, one of whom was Quander, and then later positively identified Quander at a lineup and at his criminal trial, the attorney said.

In June 1978, a year after the holdup and while Quander was in jail, police arrested Fitzgerald on an unrelated robbery charge. In Fitzgerald's possession, police found a school graduation ring that had been stolen from the robbery victim in the Quander case, DuBoff said. Fitzgerald later told police that Quander was not his accomplice, DuBoff said.