Black magic may have driven a Cambodian couple to bite off their daughter's thumb nails and suck her blood.Chheng Chhorn, 46, and Srun Yoeung, 37, attacked their 12-year-old child before dawn on Thursday while she was still asleep, biting off her thumb nails and a small part of her nose to drink her blood, said Keo Norea Phy, a police official in Kampong Cham province where the incident occurred. Neighbors rushed to the couple's house and rescued the girl after hearing her screams, he said.After treatment at a hospital in Kampong Cham, the girl was placed in the custody of other villagers. Relatives had taken her parents to a black magic healer to chase away the evil spirit that was believed to have possessed them, the police official said.Preap Nhim, a local official, said the couple sold noodles in their village and had never before acted in a strange manner. He said they may have been driven by the spirit guarding the altar they kept inside their house.Cambodia is a Buddhist country, but many people in the countryside are deeply superstitious. Some claim the ability to communicate with the dead and cure the sick by exorcising evil spirits from their bodies.