Bill Cosby arrives with one of his attorneys, Angela Agrusa, right, for the second day of jury selection in his sexual assault case at the Allegheny County Courthouse in Pittsburgh. The case is set for trial June 5 in suburban Philadelphia. (Gene J. Puskar/AP)

The delicate issue of race has percolated beneath the surface of the Bill Cosby jury selection process, present but unspoken, ever since 100 citizens filed into a grand old downtown courthouse here early Monday morning.

It was impossible to miss that nearly half the black potential jurors settled into the same row together at the back of a large courtroom where the pool first met. Once individual questioning began, prosecutors used their first of seven possible strikes to block a black juror from being seated.

But on Tuesday, the issue of race was catapulted to the center of the trial. Defense attorneys sharply accused the Montgomery County, Pa., District Attorney’s office of engaging in the “systematic exclusion of African Americans” from the jury, an explosive charge that prosecutors vigorously disputed and that the judge in the case ultimately rejected.

The late-afternoon showdown over race underscored one of the more complex challenges in the early stages of a case in which every detail, every nuance, every fact is under intense scrutiny. Court officials here have spent two full days trying to select 12 jurors and six alternates, but they left Tuesday night having seated just 11: seven white men, three white women and one black woman.

Cosby injected race into the case even before jury selection began. In a radio interview, days before the trial started, the 79-year-old entertainer blamed racism for the scandal that has seen him accused of sexual misdeeds by 60 women over five decades and criminally charged for allegedly drugging and sexually assaulting a woman who worked for Temple University. The alleged victim, Andrea Constand, is white — a fact noted by the judge during arguments over seating black jurors. (Cosby has denied ever sexually assaulting women.)

Legal experts have said Cosby, a pioneering entertainer who was the first African American to co-star on a network television show, would benefit from having blacks on the jury. In an interview, Jo-Ellan Dimitrius, who consulted for the defense on jury matters for the O.J. Simpson trial, said “celebrity-obsessed” African American men could be ideal jurors for Cosby, especially if they’d watched or listened to trials involving celebrities.

It took more than 10 hours of feuding to seat the first African American juror, a woman who appeared to be in her 20s or early 30s, who was selected midafternoon Tuesday. Prosecutors fought vigorously to keep her off the jury, with much of the arguments taking place in the chambers of Judge Steve T. O’Neill, who is hearing the case.

As the day progressed, a clump of African American potential jurors began filing into a small courtroom here to be questioned. They were lumped together because the judge was calling people based on their juror number and the seating position they took in the original jury pool room, and so many of the African Americans had clustered at the back.

The fireworks began when a potential juror, a graying African American woman who complained of bad knees, strode into the room and took a seat at a long table across from O’Neill. The potential jurors sit a few feet away from Cosby, and attorneys from both sides ring the table.

Nothing the woman said seemed particularly controversial. But prosecutors had something on her that they hadn’t yet revealed, and Kevin Steele, the silver-haired, button-down Montgomery district attorney, moved to block her from being seated.

An air of mystery hung over the proceedings because much of the fight was taking place in chambers. But when the whole cast returned to the courtroom, defense attorney Brian McMonagle disclosed what would become a wild twist: the woman is a former Pittsburgh police detective who had been arrested. Still, McMonagle argued that she should be seated on the Cosby jury because the charges against her had been dismissed. McMonagle tried to paint prosecutors as bent on keeping African Americans off the jury.

“We believe now that we are incapable of getting a diverse jury,” McMonagle said in a booming voice..

Prosecutors countered by publicly disclosing that the woman had been accused of falsifying overtime records. Assistant District Attorney M. Stewart Ryan said that even though she wasn’t convicted, the charges “directly impact her credibility.”

Ryan also said that the woman had been involved in a lawsuit against the city of Pittsburgh. The suit had been quickly thrown out, but he argued that the woman may be unfit for jury duty because she could harbor anti-government feelings.

It was enough for Judge O’Neill. He sent the African American woman home.