PATNA, July 22 -- Security has been tightened in chief minister's office -cum-residence, Sachiwalaya and four schools in Danapur on Tuesday after receiving alleged bomb threats. The threat e-mail was received by the chief minister sachiwalaya at 7.57 am on Tuesday. A threat was received against chief minister'residence and Sachiwalya. The e-mail also mentioned the timing of the 'planned' blast. The threat was sent to joint secretary Ravi Kumar of the rural development department who lodged a complaint at the police station. The mail claimed that a bomb would first explode at the Patna Sachiwalaya around 3.11 pm on July 21 and the second blast will be at the CMO and residence at 9.11 pm on July 21. The four schools in Danapur also received bomb threats, including three prominent private schools and another school located in Danapur cantonment area. Soon after the e-mail, school administration vacated the students, teachers and staff as a precautionary measure. Police increased security throughout the area and intensified surveillance. A team from Danapur police station along with bomb squad and dog squad teams subsequently arrived at the schools and started searching the premises. An officer said the e-mail sender identified himself as a Khalistani supporter.' Danapur ASP Ajit Kumar said that four schools received threats via email. "Bomb disposal squads, dog squads and other specialized teams are thoroughly searching the entire campus," he added. The ASP said that no suspicious objects were found yet. "Police are working to identify the sender of the email and its source. Cyber experts are also being deployed," he said....