A police statement said the children, aged five, eight and 10, were found with their heads shaved and their parents kneeling beside them in a house used as a church. They were found in Boseong, a village in the south, on Saturday.
“The exact cause of the death has not been established yet, but we suspect the children passed out due to shock during the time they had been locked up and hit by their parents as they had weak immunity due to sickness,” a police official at Boseong told Reuters on Monday.
South Korean media reports said the “pastor” and his wife had a congregation of 10 followers and said they had locked up their children -- two sons and a daughter -- on Jan. 24 after they became sick with colds.
According to media reports, the man said he began the “church,” which was not recognized by existing churches, himself.
Police said the man and woman shaved the children's heads because they believed it would force evil spirits out of them. They also beat each child with a belt and fly-swatter 39 times in the morning and 39 times in the evening.
The children's hands were tied. According to police, the pastor said he was “following scripture” when he confessed to killing the children.