Updated June 18, 2017 11:50:40

Bill Cosby's trial on sexual assault charges has ended in a mistrial after jurors failed to reach a unanimous decision.

Jurors deliberated for more than 52 hours over six days before telling a judge they could not agree on whether The Cosby Show star drugged and molested Temple University employee Andrea Constand at his suburban Philadelphia home in 2004.

The judge then declared a mistrial.

Prosecutors said they would retry Cosby, who remains charged with three counts of aggravated indecent assault.

The media circus that was the Cosby trial has ended with a deadlocked jury, but for many of the dozens of women who accuse the star of molesting him, merely seeing him in court was gratifying.

District Attorney Kevin Steele said Ms Constand supported the decision to retry Cosby.

"She has shown such courage through this, and we are in awe of what she has done," Mr Steele said.

"She's entitled to a verdict in this case."

He is free on $US1 million bail.

Cosby's power 'restored': spokesman

Cosby's team declared victory, however temporary, and went on the attack.

"Mr Cosby's power is back. It has been restored," the comedian's spokesman, Andrew Wyatt, said.

Cosby's wife of 53 years, Camille, slammed prosecutors for bringing the case to court, calling Mr Steele "heinously and exploitatively ambitious" in a statement released after court adjourned.

Photo: Andrea Constand leaves court after the judge declared a mistrial. (Reuters: Ed Hille)

She also attacked the judge, the accuser's lawyers and the media.

"How do I describe the judge? Overtly arrogant, collaborating with the district attorney," she wrote in her statement, which was read by Mr Wyatt.

Cosby himself did not comment, but remained stoic as the judge declared a mistrial.

Duelling press conferences, screaming supporters and a media rush. The Cosby trial is even weirder outside, Conor Duffy writes.

Ms Constand hugged her mother, prosecutors and some of the other women who say the TV star drugged and abused them.

Her lawyer, Dolores Troiani, acknowledged the difficulty of the case, given the passage of time and the impact of the alleged drugging on Ms Constand's ability to recall details.

But she said Ms Constand is ready to go to trial again.

"She's a very spiritual woman, she believes things happen for a purpose, and I think the purpose is … it should encourage other women to come forward and have their day in court," Ms Troiani said.

Jurors struggled with verdict

The comedian's career and good-guy image were already in tatters by the time his chief accuser took the stand and described how Cosby gave her pills and then molested her.

But the jurors clearly struggled with their verdict, telling the judge on day four they were at an impasse.

Judge Steven O'Neill instructed them to keep working toward a unanimous decision.

On Saturday, they came back and told Mr O'Neill they were hopelessly deadlocked.

The judge sought to comfort the jurors, at least one of whom fought back tears, calling their epic deliberation "one of the more courageous acts, one of the more selfless acts that I've seen in the justice system".

"I feel bad for all of you, I really do," he added.

He reminded prosecutors and the defence that "a mistrial is neither vindication nor victory for anybody".

It was the only criminal case to arise from allegations made by more than 60 women that cast Cosby as a serial predator who gave drugs to women before violating them.

AP

Topics: people, courts-and-trials, sexual-offences, arts-and-entertainment, united-states

First posted June 18, 2017 04:58:26