The jury remained deadlocked on other charges, including rape, against the officer, Michael Pena, 27, and was still deliberating. The Police Department terminated Mr. Pena’s employment upon his conviction.
The jury was ordered to continue deliberating on Wednesday on two rape counts and two additional charges of predatory sexual assault after a report of bias was made against one juror, who had been a senior adviser to Gov. Eliot Spitzer.
The victim, a teacher who was waiting for a ride to her first day in a new job when Mr. Pena grabbed her that morning, gasped and sobbed as the jury forewoman read the verdict. The victim then left, surrounded by supporters, without commenting.
The partial verdict in State Supreme Court in Manhattan came after a member of the jury told the judge that another juror, whom he identified only as Lloyd, had mentioned that his former law partner, Richard Aborn, had run against the Manhattan district attorney, Cyrus R. Vance Jr., in 2009. The complaining juror said he felt that the other juror had held the prosecution to an unduly high standard.
“It’s something that I’m aware of that I wanted your advice on,” the complaining juror told Justice Richard D. Carruthers.
The judge instructed the juror not to mention his concerns to the other jurors or to let them affect how he viewed the case and the deliberations, and then sent him back to the jury room.
Mr. Vance’s office soon discovered that “Lloyd” was Lloyd E. Constantine, who not only had been close to Mr. Aborn, but also knew Mr. Vance. Mr. Constantine is best known as a mentor, law partner and former adviser to Mr. Spitzer.
Just after noon, Justice Carruthers told the lawyers that one juror’s “social relationship,” which “might have some relevance” to the trial, had been brought to his attention.
The judge and lawyers interviewed Mr. Constantine in one side of the courtroom. Speaking quietly and without a microphone, he said that he had played tennis with Mr. Vance and acknowledged that he had been a law partner of Mr. Aborn’s.
Mr. Constantine said he had not been asked any questions during the jury interview process before the trial that would have required him to divulge those relationships. He said that he decided on his own that the relationships would not impair his impartiality and that to disclose them without prompting would be “a blatant attempt on my part to get out of” jury duty.
Mr. Pena’s lawyer, Ephraim Savitt, said later that the complaining juror had said he felt that Mr. Constantine had brought bias to the deliberations and “might not be fair and impartial.” But Mr. Savitt did not seek to have Mr. Constantine removed from the jury and replaced by an alternate.
“He’s saying he’s neutral, and I’m willing to accept that,” Mr. Savitt said outside the courtroom.
Mr. Spitzer and Mr. Constantine became estranged after Mr. Spitzer resigned amid revelations that he had patronized prostitutes, and Mr. Constantine wrote a book, “Journal of the Plague Year: An Insider’s Chronicle of Eliot Spitzer’s Short and Tragic Reign.”
In his book, Mr. Constantine blamed Mr. Spitzer’s dalliances in part on his giving up tennis dates with Mr. Constantine.
“The lack of tennis with me, or anyone else, had also deprived Eliot of an important physical release,” he wrote.
Mr. Vance attended the opening and closing arguments in the case but apparently did not notice or recognize Mr. Constantine. His office declined to comment because the trial had not ended.