A 19-year-old Pennsylvania woman with cerebral palsy who authorities allege was killed inside her home by her younger sister earlier this week suffered multiple stab wounds, an autopsy showed.

Helen Miller, of Manheim Township, died of "multiple stab wounds to body" early Monday, Lancaster County Chief Deputy Coroner Eric S. Bieber confirmed to Fox News in an email on Thursday. Her death was ruled a homicide.

PENNSYLVANIA WOMAN, 19, FOUND STABBED TO DEATH HAD CEREBRAL PALSY; SISTER, 14, FACING MURDER CHARGE

Initial reports from authorities said Helen had "a stab wound in her neck."

No further details were immediately provided as the police investigation continues.

Claire Miller, 14, was charged as an adult in the death of her sister Helen because homicide is not considered a delinquent act in Pennsylvania, officials said. (Lancaster County District Attorney)

Claire Miller, 14, was taken into custody at the scene Monday and charged with murder as an adult in the death of her sister.

The teen had called police just after 1 a.m. Monday to report that "she had killed her sister," the Lancaster County District Attorney's Office said.

Claire Miller brought responding officers to a bedroom where they found Helen lying on her back with her hands near her head and a blood-stained pillow covering her face, according to a police complaint obtained by Lancaster Online.

Investigators determined that Helen had been stabbed with what was described as a "large knife" sometime overnight while the girls' parents were sleeping.

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Authorities have told Fox News that Helen had cerebral palsy and used a wheelchair.

No motive has been released as of Thursday.

Claire Miller was denied bail and remained jailed at the Lancaster County Prison. A preliminary court hearing was set for Friday.