Silchar: A "secret route" used by cattle smugglers from Bangladesh to enter India has been unearthed by police in Karimganj district of Assam.

The route is located at Madanpur, a village near the Indo-Bangladesh border under Karimganj North constituency, around 80km from here, Nilambazar police station officer-in-charge Liton Nath told The Telegraph on Thursday.

It is a man-made tunnel, around 16 metres in length, fitted with a large diameter drain pipe and surrounded by dense forests. It runs under the border fence with one end opening in Bangladesh and the other in Karimganj, Nath said. Cows, buffaloes and other animals are tied and dragged through the tunnel to Bangladesh.

Karimganj, around 55km from here, shares a 92km border, of which around 41km is riverine, with Sylhet division of Bangladesh.

Nath said the matter came to light during the interrogation of two cattle thieves, Samsul Islam and Atabur Rahman, who were arrested on Sunday night. They confessed that this was the fourth time they had entered India through the route.

The two, who hail from Barlekha in Moulvibazar district of Bangladesh, had tried to attack the police with sharp weapons. They were produced before a court in Karimganj district on Monday and were sent to police custody for three days. They will be sent to judicial custody on Friday, Nath said.

Complaints about rampant cattle thefts have been pouring in from villages across the district, especially in the past six months, sources said.

Former Karimganj North legislator Mission Ranjan Das, who is now the chairperson of Assam Industrial Development Corporation Limited, said he had received reports of the "secret route" from various circles. "There has been an upsurge in cattle theft across the district. Around 30-32 cows have been stolen from Madanpur in the past two to three months. Four to five days ago, some buffaloes were stolen from the border village of Kurikala. The smugglers took away the animals by cutting the border fence," Nath said and expressed dissatisfaction over the role of the police and BSF.

He suspected that many "secret routes" exist in the district and demanded a thorough investigation. He said stern measures should be taken to curb cattle theft. He said he would personally visit the "secret route" spot and speak to the authorities.

Karimganj North legislator Kamalakhya Dey Purkayastha said he had spoken to border officials two months ago and asked them to tighten security following frequent incidents of cattle thefts but nothing had been done. He blamed the BSF for increase in cattle thefts in the district and said he would soon speak to the authorities again.

BSF sources said shortage of manpower makes it difficult to maintain round-the-clock tight vigil in the area.

Karimganj superintendent of police Gaurav Upadhyay was not available for comment.