The retrial of comedian Bill Cosby on sexual assault charges begins Monday in the suburban Philadelphia town of Norristown, Pa. Here’s everything you need to know.

Why is Cosby being tried a second time?

Cosby’s first trial on charges of drugging and sexually assaulting Andrea Constand, a former Temple University women’s basketball official, ended in a mistrial on June 17.

Jurors deliberated for 52 hours but said they were hopelessly deadlocked. After the mistrial was declared, Montgomery County, Pa., District Attorney Kevin Steele immediately announced that he would retry Cosby.

How will this trial be different from the first?

The shape of the case was dramatically altered by a major judicial decision in advance of the retrial that will allow five previous accusers to testify as prosecution witnesses. The ruling by Steven T. O’Neill, the Montgomery County, Pa., judge overseeing the case, gives prosecutors a huge opening to press their argument that Cosby is a serial sexual assaulter.

O’Neill had allowed only one previous accuser to testify at the first trial. But this time, he was swayed by prosecution arguments that a Pennsylvania court decision issued after his ruling in the first case changed the legal landscape regarding testimony from past accusers. In that case, a Pennsylvania Supreme Court judge referenced a legal concept called the “doctrine of chances,” which essentially says that the more times the same person is accused of the same type of crime under the same circumstances, the less likely it is that accused was innocently involved in those situations.

In the first trial, the jury was selected in Pittsburgh because of defense concerns about pretrial publicity in the Philadelphia area. This time, the defense did not ask for the jury to be selected in another jurisdiction, so the panel will be culled from the same area — Montgomery County, Pa. — where the retrial will be held.

Cosby has new attorneys. His previous defense team was headed by Brian McMonagle, a highly respected Philadelphia defense attorney who pounded the defense table during a high-octane closing argument in which he lambasted the media for giving a forum to 60 women who have publicly accused Cosby of harassment, sexual assault or rape. McMonagle, who at times seemed to clash with Cosby’s public relations team, withdrew from the case after the mistrial without explanation.

Cosby’s defense is now headed by Thomas Mesereau, a famed Los Angeles attorney who won an acquittal for pop star Michael Jackson on child molestation charges.

What are the criminal charges against Cosby?

Cosby is accused of three counts of aggravated indecent assault for allegedly drugging and sexually assaulting Constand at his suburban Philadelphia home in early 2004. Each count carries a maximum prison sentence of 10 years.

Why are the charges related to only one woman?

At least 60 women have publicly accused Cosby of rape, sexual assault or sexual harassment between the 1960s and 2000s. The statutes of limitation have expired for most of their cases, preventing the accusers from seeking criminal charges.

Criminal charges were filed against Cosby in the Constand case just before the expiration of Pennsylvania’s statute of limitations.

Who are the possible key witnesses?

Andrea Constand

Legal experts say much of the case rests on the credibility of Cosby’s main accuser. Constand, a former professional basketball player with an easygoing manner and a mound of curly brown hair, testified at the first trial in a voice that cracked with emotion.

Fighting back tears, she described how her vision blurred after the legendary comic gave her pills. “I told Mr. Cosby that I had trouble seeing him,” she told jurors. “I could see two of him.”

Under cross-examination, Constand struggled to explain inconsistencies in her statements to investigators — including the date of the alleged assault and whether she maintained contact with Cosby.

Gianna Constand

Andrea Constand’s mother proved to be a formidable witness at the first trial, offering testimony about a call she secretly recorded with Cosby and about other conversations with the man she believes sexually assaulted her daughter.

She told jurors that Cosby told her in a call she did not record that “he was sorry for what he did.”

In a memorable exchange, she brusquely batted away a suggestion by a defense attorney that Cosby never confessed to her. “You’re wrong,” Gianna Constand said to defense co-counsel Angela Agrusa.

The past accusers

Prosecutors have said they will call five women who allege they were sexually assaulted by Cosby between 1982 and the mid-1990s. The best known accuser is Janice Dickinson, a former supermodel who has made frequent and often emotional television appearances to lay out her claim that Cosby drugged and sexually assaulted her at a Lake Tahoe hotel. Dickinson says Cosby gave her a blue pill that immobilized her arms and legs and left her unconscious, and that she awoke with a “sharp pain in her buttocks.”

Dickinson’s attorney, Lisa Bloom, said in an email that the former model is “ready, willing and able to testify truthfully about her experience.”

Another accuser, Janice Baker-Kinney, was a bartender at Harrah’s Reno. She says she became “fuzzy” and “woozy” after taking two pills at a house in Reno where Cosby had lured her with promises of a party that never materialized. Heidi Thomas, a model who also is slated to testify, says she, too, was drugged and assaulted by Cosby in Reno.

Two other witnesses — Chelan Lasha and Lise-Lotte Lublin — say they were drugged and sexually assaulted by Cosby in his suite at a Las Vegas hotel in the mid- to late 1980s. Lasha says she believes Cosby slipped a drug into a glass of Amaretto he gave her. Lublin says Cosby gave her two drinks, saying they would help “relax” her.

Prosecutors have signaled that they do not plan to call Kelley Johnson, the one previous accuser who was allowed to testify at Cosby’s first trial. Johnson sobbed on the witness stand while recounting her allegation that Cosby drugged and sexually assaulted her at a Los Angeles hotel.

Defense attorneys fought to keep the women from testifying, arguing that their presence would in effect create a series of “mini-trials.” Cosby’s attorneys also said they would have difficulty preparing to defend against the accusations because the allegations are so old that vital records may not be available and key witnesses may have died. Two weeks before the retrial, Judge O’Neill rejected a last-minute request by the defense to delay the trial to give the Cosby attorneys more time to prepare a defense against the allegations of the past accusers.

Marguerite "Margo" Jackson

The saga of Jackson’s possible testimony was one of the stranger episodes of Cosby’s original trial. Jackson is a Temple University academic advisor who has said that she traveled with the school’s women’s basketball team while Constand was the squad’s operations manager. Jackson says that Constand told her that she could lie about being sexually assaulted by a celebrity, then file a lawsuit and collect enough of a settlement to start a business.

Jackson’s testimony was blocked by O’Neill during the first trial, though his reasons for that decision were not publicly disclosed. Cosby’s public relations team cited that ruling while making a blistering statement outside the courthouse during jury deliberations in the first trial, accusing the judge of lacking impartiality.

But, this time, O’Neill made the surprise decision to allow Jackson to testify at the retrial. Defense attorneys have said Jackson’s testimony is critical to their efforts to persuade jurors that Constand was motivated by greed.

Who will challenge Andrea Constand?

One of the toughest decisions for the defense will be deciding who will cross-examine Constand. Because of the delicate nature of the accusations, which include graphic references to sexual contact, some legal experts believe it would be wise to have a woman handle the questioning of Cosby’s main accuser.

In the first trial, Constand was cross-examined by Agrusa, a prominent Los Angeles attorney whose lack of experience in criminal trials showed as she fumbled with her notes and was repeatedly upbraided by the judge for not following proper procedures.

Mesereau, Cosby’s lead attorney, hasn’t said whether he’ll handle cross-examination of Constand. He could turn to one of the two high-powered women on Cosby’s defense team, each of whom played large roles in pretrial hearings. Kathleen Bliss is a former federal prosecutor with a commanding courtroom presence who warned Judge O’Neill during a hearing that she can be “strident” at times. Becky S. James, also a former federal prosecutor, is best known for her work on appeals.

What's the strongest evidence against Cosby?

Cosby gave extraordinary testimony in 2005 and 2006 during a lawsuit filed against him by Constand. (The case was eventually settled for an undisclosed amount.) The Associated Press filed a lawsuit in late 2014 to unseal the testimony and details from the full deposition were later reported by media outlets, including the New York Times and The Washington Post.

Over the course of four days of questioning, Cosby admitted to acquiring quaaludes, a powerful sedative that was once a popular recreational drug, to give to women with whom he wanted to have sex in the 1970s.

Cosby also testified in sometimes cringe-inducing detail about his sexual contact with Constand but characterized it as consensual. In the deposition, Cosby acknowledged giving pills to Constand but said they were the over-the-counter allergy medication Benadryl.

In one passage of the deposition shown to the jury in Cosby’s first trial, the entertainer described what was going through his head while he spoke about the sexual encounter with Constand’s mother: “I’m thinking this is a dirty old man with a young girl.”

What are the biggest weaknesses of the prosecution case?

There appears to be no physical evidence to support Constand’s allegations. She was not examined by a doctor after the alleged incident. She did not contact police until a year later, and there are several inconsistencies in her statements to investigators that could be used to undercut her credibility.

Though the criminal case was filed just before the expiration of Pennsylvania’s statute of limitations, it will be going to trial more than 14 years after the alleged incident.

In the first trial, Cosby’s attorneys barely mounted a defense case, calling only one witness — a police officer who testified about the authenticity of records that had already been shown to the jury. In the lead up to the retrial, Cosby’s new team of defense attorneys has indicated it will attempt to paint Constand as “greedy” because she settled a lawsuit against Cosby related to the alleged assault. The defense attorneys have said that they will produce travel records that show Cosby could not have been at his suburban estate at the time of the alleged assault and phone records that they hope will undercut Constand’s version of events.

Will Cosby testify?

Defendants are not required to testify, and — as expected — Cosby did not take the stand in the first trial. The one slim caveat is that Cosby is extremely adept at charming audiences, and the defense could decide that the risks of testifying would be outweighed by the benefits of having the lifelong entertainer — once known as “America’s Dad”— speak directly to the jury. Cosby also could earn sympathy points because he claims to be legally blind.

Who are the main courtroom players?

Judge Steven T. O’Neill

O’Neill, who has been a Montgomery County judge since 2002, drove the jury hard in the first trial, keeping the panel at the courthouse for deliberations late into the night. He can be folksy and chatty with jurors and is prone to whistling loudly as he strolls the courthouse hallways. But he can be sharp and biting with attorneys and is known for his lengthy and wordy discussions of even minor and seemingly uncomplicated issues.

He has imposed tight restrictions on the public and the media, refusing to allow reporters and others in the audience to leave the courtroom — even for bathroom breaks — and return. But he has sometimes been deferential to Cosby, including offering condolences for the death of the comedian’s 44-year-old daughter, Ensa, who recently died after battling kidney ailments. In the first trial, he also allowed Cosby’s wife, Camille, to enter the courtroom in the middle of proceedings, a courtesy extended to almost no one else.

O’Neill’s decision to block 12 of the 13 previous accusers prosecutors had hoped to call as witnesses was one of the key turning points in the first trial. Still, after the mistrial was declared, Cosby’s wife, Camille, issued a blistering statement calling him “Overtly arrogant in collaborating with the district attorney.”

Montgomery County District Attorney Kevin Steele

Steele, a career prosecutor, swept into office in 2015 after an election race in which the Cosby saga played a key role. Steele’s opponent in that race was Bruce Castor, the former district attorney who had decided not to prosecute Cosby in 2005. Steele used that decision to his advantage, running an advertisement that said Castor “was not looking out for victims.”

In a scorching closing argument at the first trial, Steele’s voice dripped with scorn as he described how Cosby has admitted to leaving Constand sleeping on his couch after their sexual encounter, and going to his own bedroom.

“You do what you do to her, and then you leave?” Steele said. “You leave her there? No blanket? No nothing? Clothes up around her? C’mon Come on!”

Lead defense attorney Thomas Mesereau

Mesereau cuts a striking figure in the courtroom with his long, brilliantly white hair that a Post writer once described as a “Prince Valiant pageboy.” He’s best known for winning an acquittal in 2005 on child molestation charges against pop star Michael Jackson.

A frequent television commentator, Mesereau defended television star Robert Blake during pretrial hearings in the television star’s murder trial (though he withdrew from the case before it went to trial) and represented boxer Mike Tyson in a sexual assault investigation that ended with no charges being filed.

Some of Mesereau’s first moves in the Cosby case have been controversial. He accused Steele’s team of prosecutorial misconduct, alleging in a widely covered court filing that county investigators failed to disclose that they had met with a witness who might have helped Cosby’s defense in the first trial. Cosby’s previous defense attorney, Brian McMonagle, refuted that assertion, and Mesereau was forced to walk back his allegation of prosecutorial misconduct.

Where's the family of 'America's Dad?'

Camille Cosby, the comedian’s wife of more than a decade, skipped all of the first trial, except for the closing defense argument. She has not played a role in the criminal case, but she was deposed at length in a civil defamation suit filed against her husband by several accusers that is still pending in Massachusetts.

Two of Cosby’s children — Ensa and Ennis — are deceased. His two living adult children — Evin and Erinn — did not make appearances at the first trial. But Erinn did a radio interview before the first trial in which she said, “What my father and family have had to endure these last few years makes me ashamed of our country today.”

In a twist, Erinn’s father is now being represented by Mesereau, the same attorney who once represented Tyson, a boxing champ Erinn accused of rape in a separate incident. No charges were filed against Tyson after Erinn made public accusations against him.

Keshia Knight Pulliam, the actress who played Cosby’s television daughter Rudy Huxtable, appeared for the opening of the first trial, walking into the courthouse arm-in-arm with the aging comedian. In advance of the retrial, Lisa Bonet — who played another on-screen daughter, Denise Huxtable, on “The Cosby Show” — said in a much-discussed magazine interview that she sensed something was amiss on the set of the program. “There was no knowledge on my part about his specific actions,” Bonet told Net-a-Porter. “There was just energy. And that type of sinister, shadow energy cannot be concealed.”

Once the retrial ends, will that be the end of Cosby's legal troubles?

Far from it. Cosby has racked up a series of victories in civil cases filed against him by accusers. But many civil cases remain. He’s facing defamation lawsuits or appeals of defamation suits in Massachusetts and California, all filed by accusers who say their reputations were damaged when Cosby or his representatives said they weren’t telling the truth. He also faces a sexual battery lawsuit in California.

If Cosby is convicted, the defense would have an opportunity to appeal. If another mistrial is declared, the prosecution would not be prohibited from seeking another trial. But some legal experts say they’d be unlikely to do so.
“There does come a time in every prosecutor’s life when you say, ‘Holy cow, are we going to do this again?’” said Lynne Abraham, a former Philadelphia district attorney.