The Enforcement Directorate has sought BSF help in the search for Trinamul leader Shahjahan Sheikh, whom the central agency suspects to be hiding in the Sunderbans delta and looking to escape to Bangladesh.

Shahjahan and his “associates” face a police case over the mob violence on ED officials who had raided his home in Sandeshkhali, North 24-Parganas, on Friday in connection with a probe into alleged PDS corruption.

Shahjahan, “untraceable” since Friday, could be trying to sneak into Bangladesh through the waterways, according to intelligence gathered by the central agency. The ED has issued a lookout notice on Shahjahan.

“There is a possibility that he has fled to the southernmost part of South 24-Parganas and is hiding among the fishermen tribes among whom he enjoys considerable clout,” an ED official said.

While the Bengal police are officially looking for Shahjahan, the ED, which deals with financial crimes, is also informally trying to locate him with BSF help. Sources said the BSF, which guards the international border on that stretch, had intensified its vigil to help capture Shahjahan.

The India-Bangladesh border is highly porous and is unfenced at several places because of the presence of rivers and other water bodies.

“The easiest way to cross the border is through the waterways where there is no physical barrier. The BSF watches the waterways, too, but the porous border makes the job very challenging,” a senior Bengal police officer said.

The state police have registered three FIRs in connection with Friday’s incidents.

The first case, based on a complaint from Shahjahan’s family, charges the central agency with house trespass, mischief and criminal intimidation.

The police registered the second case on their own. It is against an “unknown mob” and invokes the penal sections of unlawful assembly, rioting, assault on public servants, hurt, mischief and destruction of public property.

The third FIR was registered on a complaint from the ED against Shahjahan and his associates, and includes charges of unlawful assembly, rioting, assault on public servants, hurt, mischief, theft and destruction of public property.

No arrests had been made in any of the cases till late Sunday evening, the police said.

An officer said the police were trying to locate the source of an audio clip, circulated on Saturday, in which a male voice claiming to be Shahjahan’s appeals to all Sandeshkhali residents to continue supporting Trinamul and Mamata Banerjee.

ED officials say they have intelligence that Shahjahan was inside his house during Friday morning’s raid. They have alleged that a mob of around 200 men and women prevented the agency from breaking open the door that was allegedly locked from inside.