JACKSONVILLE, Fla. -

A 55-year-old Jacksonville woman could face life in prison after pleading no contest to second-degree murder in the killing of her 24-year-old daughter in December 2011.

Silvana Catignani also pleaded no contest to possession of controlled substances with intent to distribute, prescription drug fraud, and tampering with evidence.

A sentencing hearing is set for July 8.

Police said Catignani and her daughter, Nicole Catignani, got involved in an argument, and they said Silvana shot Nicole once in the head through a pillow.

Detectives said instead of calling 911, Silvana left the house to get rid of the gun.

Police said inconsistencies in her story and cellphone records led to her arrest. They said the records reveal she wasn't where she claimed to be.

Police said Silvana told them she threw away her pistol two months before the shooting, but two people told police they saw her with the gun the night before.

Police said the mother and daughter were running a pill operation out of their Mandarin home.