Det Sgt Alex Pockett said: “When the police arrived, the victim had her head held down, it was clear she was extremely scared.”
Sam Jones, prosecuting, told the jury: “By the late 1990s it appears the woman disappeared into a black hole. Not a single meeting that left a record or a single sighting of her outside the house.”
Since being rescued, K is now living with a foster family, attending college and has been on holidays abroad.
Wixon was released on conditional bail and will be sentenced on 12 March.
As Wixon left court she was asked what she had to say to her victim and replied: “Not a lot.”
Asked if she was sorry, she said: “No. I never done it.”
Reporters asked if she was a “monster”, as she stopped to light a cigarette, and she replied: “Say what you think.”