Thiruvananthapuram, June 25 -- The Central Bureau of Investigation (CBI) on Thursday filed a First Information Report (FIR) against former Kerala police chief Sibi Mathew, former Intelligence Bureau deputy director R B Sreekumar and 16 other police personnel over alleged conspiracy behind the framing of Indian Space Research Organisation (ISRO) scientist Nambi Narayanan in a 1994 spy case....