I am a fan of detective fiction and have read all the Sherlock Holmes stories and novels and also most of ACs novels and plays particularly the ones with the Belgian detective, M. Hercule Poirot.
In this movie, I could see traces of the Hound of Baskervilles (Sir Arthur Conan Doyles Sherlock Holmes novel) and also a bit of Sittaford Mystery by AC (AC means Agatha Chritsie, I am using the term for sake of brevity). Man, Sittaford Mystery is frightful in the beginning. I also remember seeing something like this on Byomkesh Bakshi (a DD serial aired few years back). However, Nerariyan CBI is an original idea and credit should be given to S.N. Swami and K. Madhu. Mammotty is excelling himself now-a-days except for his role in that Nayantara starrer (forgot the name also) with his weird make-up.
In this movie, some more suspense could have been added by making the corpse show blood in its mouth (which could be later explained as the blood that flowed when the finger was bitten) and kumkumam spewn around (which could be later explained by the presence of horrible ghost). I will not give details so as not to do injustice to other MS members reading this who are yet to watch the movie.
BG score was good and the tune is now on par with the famous James Bond score. Would suggest K. Madhu to have this copyrighted or TM registered.
Story was lacking in terms of CBI investigating this matter. Investigation angle was very minimal. Legal procedures were also not properly explained. Linking of the drowning in the pond of the guy who came from some foreign land (as it comes out in the dilaogues) could have been linked to the death of this girl and that would have added to the thrill.
Also, the peculiar behaviour of the police dog in the room and the mysterious shaking of lamps etc in that room was not explained properly. George Nair was quite hilarious. The IPS guy was looking like a kathakali artist more and policeman less.
On the whole, it is a watchable movie and there is no boredom at all. I am waiting for the next investigation by Sethurama Iyer. Meanwhile Peppa pe pe pey, peppa pa pe pey.....