A mother has admitted leaving her newborn baby to freeze to death in a plastic bag on a remote rural road in Illinois.
Katie Stockton pleaded guilty to first-degree murder for the 2004 death of the infant, who became known as Baby Crystal.
Stockton is also believed to be the mother of two infants found dead in her car.
She was not arrested for Baby Crystal's murder until 2009, but when she was police officers discovered her car, which had been sitting in an impound for a year.
In the car they found the remains of two children wrapped in cloth and stuffed in separate plastic bags.
Authorities have said DNA testing found Stockton was probably the mother of those two infants, but she has not been charged in relation to those deaths.
Stockton was questioned about Baby Crystal's death in 2004 after the newborn's frozen remains were found along a dead-end road near her parents' home.
Prosecutors said that when detectives interviewed Stockton hours after the discovery, she lifted her shirt and asked if she looked like she had just given birth.
Stockton refused to provide a DNA sample but detectives investigating the death collected evidence from a cigarette butt they saw her discard.
Authorities said saliva on the cigarette butt matched blood found on the clothing with Baby Crystal.
After reaching an agreement with prosecutors, Stockton admitted the murder.
Winnebago County State's Attorney Joe Bruscato agreed to drop other charges in the case.
Stockton faces up to 60 years in prison when she is sentenced on April 5.