A total of 31 persons have been named in chargesheets filed by the NIA in four separate cases linked to alleged road blockades and illegal detention of judicial officers engaged in the Special Intensive Revision (SIR) in West Bengal's Malda, officials said on Tuesday.

The chargesheets have been filed before the NIA special court, Kolkata based on various digital/technical, documentary and oral evidence, as well as examination of several witnesses to the incidents that rocked the region ahead of the assembly polls in April.

Specific roles played by each of the accused have been detailed in the chargesheets, which clearly establish their involvement in the road blockades and illegal detention/restraint of judicial officers engaged in the SIR of electoral rolls at various locations in Malda district, a statement issued by the National Investigation Agency said.

The NIA, which had taken over the investigation in the cases following the Supreme Court's suo motu cognisance and directive, alleged that the accused had, in a coordinated manner, participated in unlawful assemblies, blocked public roads, obstructed the movement of government officials, and wrongfully restrained judicial officers engaged in the SIR exercise.

Their actions had interfered with the conduct of the statutory electoral exercise and discharge of official duties by public servants, the agency said.

It has been clearly established by the NIA in its chargesheets that the accused had also disrupted the law and order in the region with their unlawful activities, according to the statement.

The agency is continuing with its investigation to identify, trace and prosecute other absconding accused and suspects involved in the conspiracy and the unlawful actions that had violated constitutional and statutory processes and disturbed public life, the statement added.