Ashley Cox stood before a judge for the first time Wednesday morning, to answer to murder charges. She pleaded not guilty during her arraignment in Oldham County.

State police say the 20-year-old, from Corbin, murdered the newborn Sunday, after giving birth at a prison in Oldham County, where she was visiting an inmate.

After Wednesday, arraignment, Cox's family said they were shocked at the allegations, but they still support her.

"We were unaware of this pregnancy," Tiffany Cox, Ashley Cox's sister said. "And we strongly believe that Ashley was unaware of it too. We are not only in shock, but we are grieving this unexpected loss."

Police now say Cox stuffed toilet paper in her newborn daughter's mouth until the baby stopped breathing.

Police charged Cox with first degree murder Monday afternoon, a day after the baby's body was found.

Police say after giving birth, Cox told prison officials she had a miscarriage. She was taken to a Louisville hospital for treatment.

Once there, doctors quickly determined she had actually given birth to a full term baby.

Soon after, blood was discovered on the floor of the prison restroom. Police say the baby's body was then found in a trash can in the restroom.

An autopsy determined the baby was killed, and Tuesday, police released the new details on how they say Cox suffocated the infant.

Police say Cox was at the prison visiting a man from Whitley County. They have not said how Cox knew the man, but they do say he is not believed to be the newborn's father.

Cox is now being held at the Oldham County Jail. In addition to the murder charge, she's also charged with concealing the birth of an infant.

She's scheduled to be back in court next Wednesday for a hearing.