In a sudden flare up in West Bengal's northern hills, a police sub-inspector was killed and three others were injured during an exchange of fire between the security forces and the Bimal Gurung faction of the Gorkha Janmukti Morcha here on Friday, police said.

Sub-Inspector Amitava Malik was fatally shot in a forested area close to Gurung's residence at Patlebas.

"The GJM workers, who were armed, started firing. While Malik died of bullet injuries, three other policemen were also injured," Additional Director General of Police, Law and Order, Anuj Sharma told .

The security forces were moving towards Patlebas after receiving specific inputs that GJM president Gurung was camping in the area.

"Last night (Thursday), we received specific inputs that Gurung was camping on the river bed below Lepcha Bustee along with boys of GJM's militant wing Gorkhaland Personnel, and that there were lot of arms and ammunition there," said Darjeeling's Superintendent of Police Akhilesh Chaturvedi.

Early on Friday, police raided the area.

"When they were fleeing, they saw us and fired. We returned the fire," he said.

Chautrvedi said from the blood trail found at the spot, it seemed some of the GJM men also sustained injuries.

Directly implicating Gurung for the death of the cop, Sharma said: "It all happened under Bimal Gurung's leadership" but also conceded that the heavy and sudden firepower caused casualties among the police contingent.

The clashes went on for hours.

Later, police recovered nine AK 47 rifles, a Berretta pistol,a point 22 bore rifle, a musket, a radio manpack, over 1,800 rounds of ammunition, 20 gelatine sticks, more than 1,000 detonators, camping materials, a sophisticated binocular and batteries.

Sharma said, during the clashes, Gurung and his close associates fled to the neighbouring state of Sikkim.

One person has been arrested, said Chaturvedi, but refused to give out his identity.

"He has disclosed certain things. The camp was continuing for a couple of months, and Gurung himself used to stay there. We have also got some identity documents," said the SP.

Accusing Gurung of having links with Maoists and northeast insurgent groups, Sharma said the beleaguered GJM leader wanted to disturb the peace process.

"Gurung has lost his base, mass support. Since he is cornered in the region, he wants to disturb the process of peace and development in the area. He has prepared a blueprint to foment trouble for his personal gain," he said.

Meanwhile, the state cabinet passed a proposal to give jobs to the widow and father of the slain policeman, who was only 27 and had married seven months back.

Chief Minister Mamata Banerjee has also released Rs 5 lakh from her relief fund for Malik's bereaved family.

Gurung has been on the run for quite some time, with the state police slapping cases under the stringent Unlawful Activities Prevention Act, as also for waging war against the government and organising terrorist camps.

The GJM, that has been spearheading the revived movement of Gorkhaland in the hills, is now a divided house, with a section of activists remaining with GJM chief Gurung while another faction has shifted allegiance towards expelled party leader Binay Tamang.

Tamang has been made the chairman of Board of Administrators of the Gorkhaland Territorial Administration by the state's Mamata Banerjee government.

Life had come to a standstill for 104 days in Darjeeling and its neighbouring hills district Kalimpong for 104 days after the GJM called an indefinite shutdown on June 12 to press for Gorkhaland.

The shutdown was lifted on September 27, hours after Union Home Minister Rajnath Singh appealed to the GJM to call off the over three-month-long strike and invited them for talks to find an amicable solution to the issue.

Significantly, the violence returned to the hills three days before a meeting called by the state government to find a solution to the Darjeeling issue.

The Chief Minister is scheduled to attend the October 16 meeting at the state secretariat Nabanna.