Dehradun/Haridwar, Feb. 19 -- The Special Task Force (STF) of Uttarakhand Police has launched an investigation into a series of bomb threats emailed to courts across the state, as the Dehradun district court received the latest threat on Wednesday, police said. Over the past three days, similar threats surfaced at courts in Nainital, Uttarkashi, Rudraprayag, Haridwar, Pithoragarh and Tehri Garhwal, prompting heightened security measures, police added. Senior superintendent of police (STF) Ajai Singh said preliminary probe indicate the threats are hoaxes. "We have initiated an investigation into the matter. The emails seem to have been sent using a VPN to conceal the sender's identity," he said. On Wednesday, a major security operation unfolded at Dehradun district court after it received a similar email threat. Police evacuated the complex and cordoned off the area. Bomb disposal squad (BDS) and dog squads carried out thorough checks across the premises. Dehradun superintendent of police (city) Pramod Kumar said the court administration alerted them to the threatening email. "The campus was immediately vacated and cordoned. Bomb disposal squad (BDS) and dog squads conducted thorough checks from the basement to all floors, including washrooms. No suspicious object was found during the search," he said. Meanwhile, security tightened at Haridwar district court after a bomb threat email arrived late Tuesday. Sent to the court's official email ID, it claimed 12 RDX explosives had been planted across the premises. SSP, Haridwar, Navneet Singh said bomb disposal squads, anti-sabotage teams, sniffer dogs and SIDCUL police personnel searched the entire complex. "No explosives were found. The cyber cell is tracing the sender of the email," he said....