The parents of two boys and an occult practitioner were among the 11 arrested in Orissa's Mayurbhanj district for sacrificing the children in the hope that it would appease the gods, police said on Thursday.
Padmalochan Gahan, 36, and his wife Minati, 30, had strangled their eldest son Harishchandra, 9, on Saturday night and their second son Deepak, 7, the following night in their home at Tilopal village in Mayurbhanj district.
Padmalochan, his wife, eight relatives and the tantrik have been arrested for not informing police and participating in the gory rituals, officials said.
The couple said they committed the crime on the advice of the tantrik, Jagannath Tudu, who had assured them the children would come back to life after the death of their last child and also bring a lot of wealth and good fortune with them.
After killing their sons, the couple was planning to kill their third and youngest child - a three-month-old girl - on Wednesday night.
They had kept the two bodies in front of the photographs of several Hindu deities in one small room of their two-roomed mud house. The bodies have been sent for post mortem.
Villagers have been shunning the couple for the past few years for practicing witchcraft.