The note said: "We can not come to a unanimous consensus on any of the counts". Jury deliberations will resume Friday morning.
These seven men and five women continue to work in a small room to determine if a man who was once one of the most famous in the world will stay a free man or become accustomed to Pennsylvania's penal system.
The 12-member jury informed the court that after almost 30 hours of deliberations, they had been unable to reach a unanimous decision.
O'Neill told jurors Thursday night, "I am proud of each and every one of you ... this is hard work you are doing".
Wyatt said Cosby is resting and has informed his wife, Camille, to inform her of the deadlock.
Later in the day, he called on the judge to declare a mistrial.
"I will not set any specific time for continuation of deliberations", he said, according to the Los Angeles Times.
The jury had earlier delivered a note saying they could not agree on a verdict on the counts of aggravated indecent assault, prompting one of Cosby's accusers to openly cry. The 79-year-old comedian is charged with drugging and molesting her at his Philadelphia-area home in 2004. Each carries a maximum 10-year prison term, though the counts could be merged at sentencing if he is convicted.
This is published unedited from the IANS feed. "I came home to my boyfriend at the time-who has been my husband, my one and only since 1990-I came home drugged and sexually assaulted by Bill Cosby to him".
The woman at the center of the Bill Cosby sexual assault trial that has a jury deadlocked tweeted a video from the courthouse suggesting she feels pretty confident.
Wyatt, during the press conference Thursday night, said this is the longest jury deliberation in Montgomery County to date.
Over the last week, numerous commentators have compared Cosby's case to the O.J. Simpson trial in 1994, which also drew extreme media attention and required a sequestered jury.
Cosby's lawyers maintain Constand was a willing sexual partner. The judge has ordered jurors to return to deliberations and try - again - to reach a decision.
Gianna Constand, the accuser's fiercely protective mother, testified that Cosby apologized over the phone to her and her daughter and offered to pay for her schooling.
Montgomery County District Attorney Kevin Steele disagreed, telling reporters, "It's a terrific jury made up of people from all demographics". In clear and firm statements, she said Cosby, a powerful Temple alum, mentored her and took an interest in her career like a father figure.
Constand won a national title with the University of Arizona and played in a pro league in Europe before landing a job with the Temple University women's basketball team.
The strongest pieces of evidence against Cosby in the case here were his admissions in police interviews and a decade-old deposition that he'd given Benadryl, which he used as a sleep aid, to Constand before their sexual encounter.
The case has helped demolish Cosby's nice-guy image, cultivated during his eight-year run as Dr. Cliff Huxtable on the top-rated "The Cosby Show" in the 1980s and '90s. In that case, prosecutors would get four months to decide whether they want to retry the TV star or drop the charges. "That's the question", said criminal lawyer Alan J. Tauber, who wasn't involved in the case.
He did not take the stand in his sexual assault trial.