Oru CBI Diary Kurippu is a 1988 Indian Malayalam-language mystery thriller film directed by K. Madhu, written by S. N. Swamy, and starring Mammootty, Suresh Gopi, Jagathy Sreekumar, Mukesh, and Sukumaran. The lead character, CBI officer Sethurama Iyer is inspired by a police officer named Radha Vinod Raju, Jammu and Kashmir cadre IPS Officer, who in 2009 was appointed as the first chief of India's National Investigation Agency. It was the highest grossing Malayalam film at that time. Considered one of the best crime thrillers in Malayalam, it eventually developed a cult following. This is the first installment in the CBI film series featuring Mammootty as Sethurama Iyer.