A 28-year-old man from Madhyamgram was arrested on Friday for allegedly spreading rumours on social media about alleged childlifters in Barasat, North 24-Parganas.

Police said 57 rumour-mongering posts on Facebook had been identified and 41 pulled down by Friday evening.

Abdul Karim was the fourth person arrested for allegedly spreading rumours that led to three persons getting beaten up at two places in Barasat on suspicion that they were child lifters.

Three persons — Pritam Mistry, Sheikh Mijanur Rehman and Payal Talukdar — were arrested on Thursday on similar charges. The police said the trio were administrators of two Facebook groups.

Barasat police have announced a helpline to report such rumour-mongering on social media platforms.

A senior police officer said on Friday that people can report suspicious posts on Facebook or other social media platforms by sending WhatsApp messages to 9163766694.

Karim, the police said, did odd jobs for a living and drove a bike taxi. He had allegedly shared multiple posts and videos aimed at spreading rumours that a gang of child traffickers was active in the area, an officer in the Barasat police district said.

“Karim had also commented multiple times on rumour-mongering posts uploaded on at least two Facebook groups,” the officer said.

Karim has been charged under the Information Technology Act and IPC sections related to mischief and causing breach of peace in society.

An officer said the 57 Facebook posts they had identified were meant to spread rumours and create panic. The posts had been made from various accounts.

The Barasat additional superintendent of police, Sparsh Nilangi, said that of the 57 Facebook posts, 41 hadbeen taken down till 5.30pm on Friday.

“We are in touch with Facebook and have asked them to take down these posts as they are solely aimed at spreading rumours,” Nilangi told Metro.

The Barasat superintendent of police, Pratiksha Jharkhariya, said the four in custody had been actively spreading rumours through two Facebook groups that a gang of child traffickers was active in the area.

“We have arrested 19 people for Wednesday’s assaulton two men and a woman,” she said.