A forest guard was killed in an alleged clash deep inside the Sunderbans on Saturday night, forest officers and police said on Sunday.

The guard has been identified as Amalendu Halder, deployed in the Sunderban Tiger Reserve (STR).

A senior forest official said Haldar and three other guards were attacked by “a group of dacoits who were apparently from Bangladesh”.

A senior police officer confirmed the death but said it was still too early to say who was responsible for it. An investigation is underway, he said.

The alleged clash is said to have taken place in the Gosaba-I forest compartment.

A statement issued by Debal Ray, the chief wildlife warden of Bengal, said: “Around 10pm on May 18, a small team of forest personnel from Netidhopani beat of STR who were patrolling on a small boat in Gosaba 1 compartment, came across a group of 10-15 dacoits, who were apparently from Bangladesh. The patrolling forest team confronted them. However, the intruders attacked the forest staff and forced them to run for life. The staff jumped into the water to save themselves.

“Three staff survived the attack but one forest guard, Amalendu Halder, died. The body of Halder was found in Morabani khal, Gosaba 1 compartment, near the place of incident. He had injuries on his head. An FIR has been lodged. Massive mobilisation of staff has taken place to apprehend the culprits who are thought to be in Indian waters. Senior officers of the STR are in the field,” the note said.

A senior officer in the Baruipur police district acknowledged the death but said it was too early to say who was behind it.

“We have registered a murder case. An investigation has begun. Prima facie, the victim suffered head injuries. The body is being sent for post- mortem. We will talk to the witnesses (three other forest guards),” he said.

On the Bangladesh link, the officer said: “The incident happened at the southernmost tip of Bengal, almost near the edge of the Bay of Bengal. Bangladesh is 200km away. The only route is through the waters. It is not easy to cover the distance. We are probing all angles. It is still too early to comment.”

The Sunderbans is spread across 10,000sqkm, a little above 4,000sqkm of which is in India. The rest is in Bangladesh. The Indian Sunderbans is split between the STR and the South 24-Parganas forest division.

The STR covers 2,585sqkm. It is made of the Sunderbans National Park (East and West), which is the core area, and the Sajnekhali Wildlife Sanctuary and the Basirhat Range, which form the buffer zones.

Ray, the chief wildlife warden, did not elaborate on what the “dacoits” were doing inside the forests.

A retired forest official, who has spent years in the Sunderbans, said Bangladeshi pirates have in the past attacked Indian fishing boats and trawlers. “They have attacked fishing vessels. They capture the boats and take them back to Bangladesh. But killing a forest guard is unprecedented,” he said.

A source in the forest department said the men who killed Halder had “possibly come to collect honey”.