The Central Bureau of Investigation has booked Karnataka cadre senior IPS officers Hemant Nimbalkar, Ajay Hilori and three other police officers in connection with Rs 4,000-crore I-Monetary Advisory (IMA) scam. Media has learnt that a case was registered against the Karnataka Police officers after the state government granted approval to investigate the alleged role of 1998-batch IPS officer Nimbalkar and 2008-batch IPS officer Hilori.