At the time of the alleged assault, Constand was the director of women's basketball at Temple University, where the actor sat on the board of trustees.
But the jurors struggled with their verdict, telling the judge on day four of the trial that they were at impasse.
Most prosecutors, faced with a mistrial caused by a hung jury, will initially insist publicly upon their dogged determination to retry the case, just as defendants will maintain that they will never agree to a plea bargain because of their strong faith in our jury system - essential postures to maintain the strongest possible bargaining position. The judge has refused, saying jurors are permitted under the law to deliberate as long as they want.
The judge in famed American stand-up comedian Bill Cosby's sexual-assault case declared a mistrial on Saturday, after the jury was unable to reach a verdict following six days of deliberations.
Constand sat in the front row directly opposite to Cosby.
The admissions smashed the image he had built as a moralizing public figure and as the upstanding paterfamilias in the wildly popular 1980s and '90s sitcom "The Cosby Show".
Massachusetts: Seven women are suing Cosby for defamation in separate lawsuits pending in Massachusetts, where Cosby has a home in Shelburne Falls.
One of the more talked about aspects of the Bill Cosby rape trial was the staunch support from former "Cosby Show" co-star Keshia Knight Pulliam and the conspicuous absence of his wife, Camille Cosby, during the first part of the trial.
In an exclusive interview with CNN's Jean Casarez, attorney Brian McMonagle said the jury's inability to reach a verdict made it clear the trial should end.
"Anything can happen because it's a new set of jurors", Levenson said. The judge then declared a mistrial. "Overtly arrogant, collaborating with the district attorney", said her statement, which was read by Wyatt and tweeted by her husband.
By Thursday morning, after almost 30 hours of discussions spanning three days, the jurors told O'Neill they were at a stalemate.
But a lawyer representing many of his accusers, Gloria Allred, said she was hoping the prosecution would push for a retrial.
The entertainer, who had an endearing reputation as "America's Dad" from his years as the lovable Cliff Huxtable on "The Cosby Show", faces up to ten years in prison on each of the three counts.
Instead she put across a venomous attack on Steele's credibility, as well as that of Judge Steven O'Neill and the media.
I feel for Constand because clearly it's not easy to take such an allegation to court.
When the deposition was unsealed by a federal judge two years ago, it was revealed he had previously admitted to giving young women sedatives in the past. Steele said he and prosecutors Kristen Feden and M. Stewart Ryan "will evaluate and review" the case.