Kolkata, Oct 23 : Threat letters to local businessmen in North Bengal demanding hefty ransom amounts by underground outfit Kamtapur Liberation Organisation (KLO), which virtually became a forgotten chapter, seems to be returning again. Recently, Binay Kumar Das, a businessman in Alipurduar district, received a threat letter reportedly sent by the KLO, demanding Rs 10 lakh from him. He has reported the matter to the local police and is extremely tensed since his residence and business centre are located close to the West Bengal-Assam border. The threat letter has been sent through WhatsApp. After receiving a written complaint, the police have launched an investigation into the matter. Veterans confirmed that such threat letters from the KLO demanding ransom amounts from local businessmen were common before 2003, when under pressure from the Indian government, the Royal Bhutan Army launched 'Operation All Clear' against Assam-based separatist and insurgent groups, which were operating from camps in the southern regions of Bhutan. However, gradually it became a forgotten chapter. District police sources said that they are taking the matter very seriously amid the recent developments wherein the Kamtapur State Demand Committee, an independent committee demanding separate Kamtapur statehood, has demanded immediate beginning of peace talks between the Centre and the banned KLO. The committee has also demanded that recently-surrendered KLO general secretary Kailash Koch, who is currently in judicial custody in West Bengal, should also be involved in the peace talks. The committee has also decided to begin a massive public awareness campaign to highlight the need for initiation of peace talks. /IANS