The accused had murdered the boy in February and held his mother captive, threatening her not to go public about the crime. The murder came to light after the mother managed to escape from their clutches and approached the police on Wednesday, after which the police arrested the accused.

The arrested persons were identified as M Murugan (44), his wife, M Bhuvana (34) and M Vinoth (20), a relative of the deceased boy.

Police said that the victim, S Suresh (15), was employed at Murugan's farm and was tasked with taking care of the goats. Suresh's mother, S Vennila (40) and her two other children, aged eight and six, also lived in the farm.

Investigations revealed that the family's relative, Vinoth, took them to the farm owned by Murugan and Bhuvana as the family struggled to make ends meet after Suresh's father died. The family had been employed there for the past eight months.

In February, Murugan and his family went to Madurai to attend a temple festival. When he returned, he found some of the goats and chickens missing from the farm, after which he and Bhuvana allegedly confronted Vennila and Suresh.

Vinoth, who had originally helped the family secure employment at the farm, also joined in the altercation. During the confrontation, the trio allegedly assaulted Suresh with a wooden log, leaving him critically injured. He died on the spot, police said.

The accused then buried the boy's body within the farm premises and threatened Vennila, and also allegedly promised her money in exchange for her silence. Police said Vennila remained confined to the farm without access to a mobile phone, and she managed to leave on Wednesday.

A team of senior police officials apprehended the accused, who confessed to the sequence of events. On Thursday, the minor's body was exhumed in the presence of revenue officials.