A detention officer who works in the cellblock at D.C. Superior Court was indicted yesterday on charges of obstructing justice by encouraging a witness in a homicide trial not to testify, authorities said.

Angela Veronica Collins, 50, an employee of the U.S. Marshals Service, is accused of approaching a witness in the cellblock and offering her "substantial amounts of money" not to testify, Assistant U.S. Attorney Michael Brittin said yesterday.

The obstruction allegedly occurred recently in the case of Michael Brown, who is charged in the 1986 slaying of Violet Rodney.

Brown also was charged with obstruction in yesterday's indictment.

The indictment said Brown, 37, asked Collins to speak to Andrea Smith, also a prisoner in the cellblock and a witness to the homicide for which Brown is to be on trial. Brown instructed Collins to offer Smith "money, incidental items of value, and other valuable incentives in return for her refusal to cooperate or testify truthfully," it charged.

Brown is still awaiting trial on the homicide charge.

Collins, who was arrested Tuesday afternoon at work, broke down yesterday during a court hearing in which she pleaded not guilty.

"No, please. Oh, God . . . " she sobbed as four of her co-workers approached her and tried to comfort her. "I didn't do those things."

Collins was hired by the U.S. Marshals Service in 1988 as a detention officer, one of about 40 who guard and occasionally transport 300 to 400 inmates daily.

Richard Oakcrum, the chief deputy U.S. marshal in Superior Court, said his office was informed of the investigation several days ago.

Throughout the afternoon, Collins was consoled by several co-workers who, at one point, shielded her from a reporter.

Collins's attorney, Archie Nichols, declined to comment after the brief hearing yesterday. But in a brief interview earlier in the afternoon, Collins denied any involvement.

"The allegation is that I'm friends with these people, but I'm not," she said.

The 10-count indictment includes conspiracy to obstruct justice, bribery and other related charges.