District Attorney Mike Taylor told a judge that new tests showed 15-year-old Ashley Mignano, who had cerebral palsy, did not die July 4 from a fatal dose of phenobarbital. The teenager's mother, Margaret Mignano, had been arrested in August and spent a week in jail before she was freed on bond.

The autopsy report was signed by Dr. Charles Harlan of Nashville, a forensic pathologist who is defending his medical license against state charges of misdiagnosing causes of death in other cases and destroying evidence in criminal investigations.

Mignano's attorney, Bob Peters, said he and Taylor were in court for an unrelated case when the prosecutor surprised him by telling a judge that "follow-up testing did not indicate a lethal dose" of the drug, used to control the girl's seizures.

The prosecutor did not immediately return a call seeking comment, but a court clerk confirmed that Taylor said the murder charge was dropped.

Harlan's report included outside lab tests showing the teen had lethal levels of the barbiturate in her system. The defense argued that Mignano, who moved her family from New Jersey about a week before the death, followed doctors' orders in using the drug.

Harlan, who continues to practice while fighting the state charges, declined to comment Friday about the Mignano case.