The girl, Sunisa Chaiyoi, was found about 5.30pm at her Chalong home by a cousin who brought her a pork and rice dinner from Phuket City, where her parents were selling fruit.
Her father Kanung, 61, and her mother are vendors inside Phuket City's Phuket Vocational College, a large technical school in Saphan Hin.
Sunisa, who usually sells fruit with her parents, went home early today with a headache. Her parents, concerned about their daughter, sent a meal home with her cousin.
He was the first to enter her bloodied bedroom, where investigating police and forensic experts were sifting through clues tonight.
The home, in Chanakan Village, Chalong, near the TOT office, sits in a middle-class housing developing where homes, like the Chaiyoi family house, mostly have three bedrooms.
Access to Sunisa's bedroom was possible from outside through a sliding window.
A hammer was close to the girl's body. It's possible she may have been raped or sexually abused, police believe.
Her lower body was covered with a green towel. She was still wearing a white top and bra.
There were no obvious blows to her head or upper body, charity foundation workers found when called to the scene.
The hammer belonged to the family. It appeared to police from the Chalong Station as though every room in the house had been ransacked.
At this stage of the investigation, police are unable to say whether Sunisa knew her killer, or whether one person or more were involved.
Sunisa was taking a year off school with health problems. Her parents had hopes of sending her back to school next year.
Her body was taken to Vachira Phuket Hospital in Phuket City, where a medical examination is expected to reveal more about her death.