BY A STAFF REPORTER : CBI has gathered evidence against senior police officers and political leaders on their role in the Birbhum. Sources close to the joint director in-charge of the special crime branch of the investigative agency mentioned that call detail records and evidence from tower dumping indicate the presence of several key suspects. ``We have grilled suspects and collected all required documents and materials. Our officers have also taken the help of technology to identify conspirators,'' a source close to the senior officer monitoring the investigations told ANM News over phone from Delhi. CBI has debunked arrested TMC leader Anarul Hussein's contention that no one spoke to him on phone. ``He was using another phone and was in touch with senior police officers and suspects. We have CDR and other technical details to nail his lie,'' an officer who is a part of the investigating team said.