"Why have the police not been able to arrest the headmistress who forced our children to eat poisonous food? She should be killed," said bereaved father Surendra Rai, who took part in the raid late on Thursday after most of the children were buried.
Many of the victims, aged four to 12, from Gandaman village, were laid to rest on a playing field adjacent to the primary school that served the free meal of rice, lentils and potatoes -- the only meal of the day for many.
Some 30 children remain sick in hospitals, mainly in the state capital Patna, officials said.
Police said they are probing whether the food or the cooking oil was accidentally or deliberately poisoned, after initial tests showed traces of insecticide. The results of forensic tests on the food are expected to be ready later Friday.