A day after a couple was lynched by a mob after a missing boy was found dead in a pond near their house, Nadia police on Sunday arrested four persons – the son and wife of the lynched couple and their two relatives – in connection with the abduction and murder of the eight-year-old boy.

“We have arrested the four persons. We will seek their custody for further investigation,” said a police officer involved in the probe.

The lynching of the couple – Utpal and Soma Biswas, in their late 40s – took place at Nishchintapur in the Tehatta area of Nadia district on Saturday morning after villagers found the body of the eight-year-old boy, wrapped in a tarpaulin sheet, floating in a pond near the couple’s home.

The eight-year-old boy had gone missing on Friday afternoon. The boy’s family accused the Biswas couple of kidnapping and killing the child.

Sources in the police said the two families were involved in a longstanding feud. “We are investigating if the murder was a fallout of past disputes or a possible case of child trafficking. Villagers have told us that Utpal was earlier accused of trying to abduct a child, and as a toto driver, he used to regularly ferry children to schools,” said a police officer.

According to a PTI report, the post-mortem report of the boy concluded that he was “strangulated to death”.

“The report confirms that the boy was murdered. A ligature mark was found around his neck. There are clear marks of strangulation. The crime took place sometime between 4 pm and 6.30 pm on Friday,” PTI quoted a police officer as saying.

In the mob attack, another son of Utpal Biswas was also grievously injured and admitted to a hospital in Kolkata.