A medical examination later confirmed rape.
The 46-year-old father is a drug addict and alcoholic, the police said. The mother has claimed ignorance. The older sister was hospitalized in Kozhikode with burn injuries in August 2010 and died soon after. She took the extreme step because she couldn't cope with the recurring sexual assault, the girl told the police.
"We have started a probe into the sister's dying declaration before a magistrate, in which she stated it was an accident. There are loose ends in the girl's claims on her sister's suicide," said Thalasserry circle inspector Vinod Kumar. The girl also told the police her sister's dying statement had been tampered with, but the officer said they didn't have evidence of this.
Seeking a thorough probe, state women's commission chairperson K Rosakutty said, "If the dying statement of the elder sister had been properly investigated, the younger one could have been saved." She said the commission would protect the minor, now lodged in a children's home.
Meanwhile, a similar incident was reported from Kottayam district on Tuesday. A man was arrested after his wife filed a police complaint saying he had sexually abused their daughters, aged 12 and 13.