The CBI film series

The CBI film series is a series of four Malayalam films directed by K. Madhu and written by S. N. Swami featuring Mammootty as Sethurama Iyer, a Central Bureau of Investigation (CBI) officer. The series started off in 1988 with the block buster Oru CBI Diary Kurippu. The films depicts a team of CBI officers led by Sethurama Iyer investigating into a murder case.