The 8km-long Belghoria Expressway, which connects Dakshineswar with Jessore Road, is a truck corridor where policemen rampantly extort money from drivers.

The mowing down of four young boys by a truck on Monday morning is believed to have resulted from one such extortion attempt.

People who live along the road and truck drivers and operators said at least four police teams were always on the prowl for money on the stretch. The expressway passes through areas covered by four police stations - Dum Dum, Baranagar, Belghoria and Nimta.

Officials of the National Highways Authority of India, which maintains the stretch, say around 700 trucks ply down the expressway daily.

Residents of Khalashikota, Adarshanagar, Niranjan Sen Nagar and Rabindranagar - all on the expressway - told Metro that police teams extorted money from truck drivers after stopping the vehicles on the pretext of scanning their papers in at least four points.

The points are Mathkol, Durga Nagar, Birati and the approach to Dakshineswar.

At night, police jeeps are usually parked under trees and cops use torch lights to direct drivers to stop.

"There is no escaping them. They will find one fault or the other and force us to shell out money," said a driver who ferries sand from Burdwan to Durga Nagar near Birati.

"Even if all the papers are in order, they will say that the driver is not wearing his uniform or carrying an authorisation letter notified by a first-class magistrate," the man in his 40s said, refusing to be named.

A transport department official pointed out that truck drivers were not required to wear any uniform.

"There are fixed rates," said Subhas Chandra Bose, the secretary of Federation of West Bengal Truck Operators Association.

"A 10-wheeler or a 12-wheeler truck has to pay Rs 300 to each police team. For smaller vehicles, it's Rs 150. On any given day four police teams will camp along the expressway."

Bose said the federation of truck operators' association had met senior officers of the Barrackpore police commissionerate in January and lodged a complaint against the practice. "We have also informed the chief minister about this in writing."

A section of drivers said truck owners would give them money to grease the palm of the expressway cops. "If we can dodge the cops at one point, the money they would have taken goes to our pocket," one of the drivers said with a smile.

Residents alleged a section of building material suppliers had struck a deal with the police so they could park their trucks on the road and unload sand and stone-chips.

Monday's fatal accident may lead to a pause in the extortion drive but is unlikely to stop it for good, many residents and truck drivers this newspaper spoke to said. "The money involved is too big and the stakes are too high," a resident said.

The Barrackpore commissionerate, which is probing the death of the three children aged between seven and 15 and the subsequent attack on the cops, said the FIR had not mentioned any attempt by men in uniform to extort money.

"A general and informal allegation that the police force truck drivers to pay them money is difficult to probe. If there are specific complaints, we will order an inquiry," Barrackpore police commissioner Niraj Kumar Singh said. "On a few occasions we have taken necessary action based on such complaints."