The incident took place at Durai Shib Bari village under Kamalpur police station on Saturday night.
The boy was 15-years-old. The deceased persons have been identified as Badal Debnath (70), Sumita Debnath (32), Suparna Debnath (10) and Rekha Deb (42).
"At around 11 pm, we got the information that a body has been recovered from a pit outside a house. When we reached the spot and excavated, our team found a total of four bodies,” said Kamalpur sub-divisional police officer (SDPO) Ramesh Yadav.
“Among the dead are three women and a man. All are from the same family. The accused is a minor and belongs to the same family. The accused is in our custody," he further said.
A case has been registered under sections 302 and 201 of the Indian Penal Code (IPC).
The reason behind the heinous crime is not yet identified. However, the police have launched thorough investigations.