Nerariyan CBI is a 2005 Malayalam film. This film is the fourth in the series of the CBI investigative thrillers.
Four years back, Anitha came home to Animangalam Tharavadu with her friends. That night her friends Mythili is found dead below the stair case. The house had a locked pooja room and the girls had tried to open it. Police came to investigate and concluded that some ghost was at work. A priest, Kappra was called to investigate who asks the family to sell the house as soon as possible.
All these were told to Sethurama Iyer when Anitha’s fiance Sai meets him in the airport. Iyer gets interested in the case and decides to investigate with the help of Chacko and Vikram. As the investigation proceeds, they find that Mythili had a lover, Pradip, whom none of her family members had seen. He did not even turn up on her death. Also when Mythili’s parents asked CBI to investigate, they were threatened by goondas to withdraw the case