A Maoist poster warning against setting up special economic zones pasted at the station. Picture by Rahul Mahato

Calcutta, June 27: The plot to set Biramdih railway station on fire was hatched four months ago and the Chandil zonal action squad of the CPI (Maoist) was assigned the job, sources close to the Maoists told The Telegraph today.

Sudip Chongdar, in charge of the squad, was, however, told not to kill any railway employee.

The sources said Chongdar, in his mid-40s, picked 40-odd men from his squad for the task — said to be first of its kind in the state. They were from Bengal and Jharkhand.

"We believe they slipped into Jharkhand by using the dense forest routes of the Dalma range," said an Intelligence Bureau official.

The sources said the decision to set the station ablaze had been taken at the party congress held in February in a Jharkhand forest. More than 100 delegates from 16 states were present.

"It was left on Chongdar, who is also a state committee member of the organisation, to select a station," the source said. "He chose Biramdih because it falls within the four areas — Bagmundi, Ayodhya, Saraikella and Chandil — where his squad operates."

Intelligence officials believe Biramdih station's location made it an easy target. "It is flanked by two ranges of hills, Dalma and Ayodhya. This would make it easy for the rebels to get to the station undetected as well as escape to Jharkhand."

According to information gathered by IB officials from villagers, Chongdar and his men had been spotted near the station for the past one month.

But IB officials believe that Chongdar had taken the villagers into confidence. "That is why we had no prior information and no one tipped us off about the strike," said an official.