A 12-year-old girl who prosecutors expected to offer damaging testimony against the mother of a deceased juvenile diabetic, backtracked significantly Thursday on the witness stand.

Appearing as a prosecution witness in the Cheryl Musso murder trial, Nicole Peron was expected by prosecutors to say that she saw Musso sitting on a couch and drinking a beer as her diabetic daughter, Ariel Botzet, was vomiting and on the verge of dying from a lack of insulin.

But that was not Peron's account when she took the witness stand Thursday. Peron said she never saw Botzet vomit at Botzet's house the day before she fell into a diabetic coma.

"When I last saw her, it looked like she was going to throw up," Peron said.

Peron also testified she never actually saw Musso drinking beer as her daughter was vomiting.

"There was a beer on the table," Peron said. "I did not see her drink it."

The testimony contradicted what prosecutors said Peron told them during a pretrial conference last week. It also contradicted what prosecutors said the girl's expected testimony would be when they addressed jurors during opening statements of the high-profile trial.

Upon further questioning, Peron acknowledged that she was well-acquainted with the defendant, and that a friend at school told Peron last week that "I better stick up for Cheryl."

Prosecutor Dave Stanton subsequently sought to call the girl's mother as a witness to show Peron had, in fact, reported earlier she saw Botzet vomiting and Musso ignoring the situation the day before Botzet went to the hospital and eventually died. But District Judge Sally Loehrer ruled the mother's testimony would be hearsay and was therefore inadmissible.

The episode was part of an otherwise successful day for prosecutors in their efforts to convict Musso of murder in the Feb. 9, 2004, death of her daughter. Authorities allege Musso engaged in a long-term pattern of neglecting the medical needs of her diabetic daughter.

On Feb. 6, 2004, the child was rushed to the hospital and later died from what authorities said was a lack of insulin.

Defense attorney Herb Sachs, however, has said there is no evidence Musso denied her daughter insulin, and Botzet was also a child who resisted monitoring her diabetes.

On Thursday, nurse practitioner Robert Lynn said he counseled Musso on how to care for her daughter's diabetes, and he particularly told Musso that if Botzet vomited, it was a warning sign that her health was in danger.

Dr. Richard Sterett, a pediatric intensivist, said he was called to University Medical Center when Botzet was brought into the hospital, and the child was suffering from severe brain swelling. Sterett testified Musso told a colleague of his that her daughter had been vomiting for up to four days prior to the trip to the hospital.

Sterett also said Musso told his colleague Botzet had vomited "15 to 20 times" in the 24 hours prior to the hospital visit.