A civic volunteer died, and two others were injured in a blast in northern West Bengal's Kalimpong police station on Saturday night, police said. The blast took place at 10.15 p.m., nearly 24 hours after an explosion in the heart of the hill town of Darjeeling that damaged few shops, triggering tension among locals though none was injured. Police have booked three top GJM leaders including its chief Bimal Gurung under the stringent Unlawful Activities Prevention Act (UAPA) in connection with the Darjeeling blast. The explosion at the Kalimpong police station left a home guard and a jawan of the Seema Sashatra Bal injured. Both the injured have been hospitalised, said Kalimpong Superintendent of Police Ajit Singh Yadav. "Civic volunteer Rakesh Routh has been killed," he said. More details were awaited. The GJM denied its involvement in the Darjeeling bladt, and demanded a probe by a high level enquiry committee comprising National Investigation Agency officials under the supervision of the Supreme Court. "There was a bomb blast in Darjeeling's motor stand area at 12.10 a.m. No one got injured as the place was empty at the time of the blast. We are investigating the incident," Superintendent of Police Akhilesh Kumar Chaturvedi told IANS. Police said the blast was caused by an Improvised Explosive Device, and the impact was felt over 40 feet. Police recovered wire from the spot. The blast took place on the 69th day of the indefinite shutdown called by the Gorkha Janamukti Morcha (GJM), which has demand a separate Gorkhaland state be carved out of the north Bengal hills. According to sources, a number of shops and the road in front of the motor stand area have been damaged. Fire tenders, police and Central Reserve Police Force personnel rushed to the spot after the blast. Police have been deployed in the area. No individual or organisation has so far taken responsibility of the blast, but the police said top GJM leaders like Gurung, Prakash Gurung and Pavin Subba were prima facie suspects. In the afternoon, police filed an FIR against these three leaders and "others" and started a case at the Darjeeling Sadar police station. "Regarding the bomblast at Darjeeling motorstand on Saturday, case has been started against Bimal Gurung, Prakash Gurung, Praveen Subba and others," a police officer said. The sections applies include 120B (Punishment of criminal conspiracy), 121 /121A/122 of IPC (relating to waging or intending to intention of waging war against the government), as also sections 16/17/18/18A/18B of UAPA (that deal with terrorism and organising of terrorist camps as also recruiting people for the same). Cases under some sections of the West Bengal Maintenance of Public Order and Prevention of Damage to Public Property have also been slapped against the accused. GJM chief Gurung, in a statement, termed the blast as "the handiwork" of those opposed to Gorkhaland and demanded an "unbiased investigation". "The Gorkha Janmukti Morcha condemns and protests against the bomb blast. The blast, we believe, was the handiwork of those who do not want Gorkhaland state to be formed. This was a planned move aimed at bringing disrepute to the movement and the demand for Gorkhaland. "The Gorkha Janmukti Morcha demands that a probe be initiated, at the earliest, by a high level enquiry committee, comprising of NIA officials under the supervision of the Supreme Court of India, so that an unbiased investigations can be carried out into this heinous attempt to bring disrepute to the Gorkhaland movement and the leaders associated with it, and wilful attempts at causing unrest in peaceful Darjeeling." He wondered how the blast could take place as the entire Darjeeling region has been "fortified and turned into a garrison of sorts" and that it occurred only 200 metres from the police station. "GJM will never support any undemocratic means, and we condemn this attempt at breaching peace in the hills. We request everyone not to be misled and not to be scared, and to maintain peace in the hills," the statement added.