Kindra Adamson was arrested on the evening of July 10, Lewis County Sheriff's officials said.
She was arrested based on her actions and knowledge of the crime, after the murder of 16-year-old Benjamin Eastman and before the arrest of the suspects, police said.
She was in court July 11, suspected of rendering criminal assistance. Adamson originally pleaded not guilty, but changed her plea to guilty on two counts of providing criminal assistance in the first degree in court on Friday.
“Our agency will continue to hold those involved in this horrific act responsible for their actions,” Sheriff Robert Snaza said. “This includes anyone else who may be identified as part of this investigation in the future.”