“When a member of the N.Y.P.D. is indicted on serious charges like these, it tarnishes all of the admirable things accomplished by other, good officers every day in neighborhoods across New York City,” the police commissioner, James P. O’Neill, said in a separate statement. Mr. O’Neill added that had the charges against the officers been upheld at the internal trial, he “would have fired them immediately.”

The departmental hearings are meant to determine what, if any, internal disciplinary actions — up to being fired — should be meted out against officers accused of misconduct. The charges in this case were not directly related to the encounter with the young woman, but stemmed instead from the officers’ refusal to answer questions about the incident from investigators with the Police Department’s Internal Affairs Bureau.

Mark A. Bederow, a lawyer for Mr. Martins, said it was unfair that investigators had sought to interview the officers after criminal charges had been filed, possibly exposing them to self-incrimination. “They were compelled to speak about the incident at a time when the N.Y.P.D. already knew that they been indicted by a grand jury and after a series of leaks attributed to police sources,” Mr. Bederow said. “We are focusing all of our effort and energy now on the Brooklyn indictment and on demonstrating that the allegations against Detective Martins are false.”

John Arlia, Mr. Hall’s lawyer, did not respond to phone calls seeking comment.

The accusations against Mr. Hall, who joined the Police Department in July 2010, and Mr. Martins, who joined in July 2006, are some of the most explosive to have been leveled against police officers in New York City in decades. Prosecutors from the Brooklyn district attorney’s office assert that the two officers took turns sexually assaulting the 18-year-old woman after they had pulled her car over on Sept. 15 and put her — in handcuffs — into their police van.

Prosecutors said that the officers had been working on the night of the encounter with their antidrug unit, Brooklyn South Narcotics, in Coney Island, but broke away from their team and stopped the woman’s car in Calvert Vaux Park in the nearby Gravesend neighborhood. After she admitted there was a small amount of marijuana and few a pills of Klonopin, an anti-anxiety drug, in the car, the officers told her that she was being arrested, prosecutors said, and ordered her two male friends, who were passengers in the car, not to follow the police van.