The prosecution must prove beyond reasonable doubt the mental capacity of the accused at the time of the offense to establish guilt.

1. This appeal is directed against the judgment and order of conviction dated 20 March, 2009 and 23 March, 2009 passed by the Learned Additional District and Sessions Judge, F.T.C, North 24 Parganas in Sessions Trial No.03(11) / 2007 arising out of Sessions Case No.28(5) of 2007 convicting the appellant under S.302 of the Indian Penal Code (IPC) and sentencing the appellant to suffer life imprisonment and also pay a fine of Rs.5000.

2. The prosecution case in brief is that information was lodged by Sri Bishnupada Baidya, the son of the Bonochari Baidya (the deceased). The information disclosed that on 28 November, 2006 in the evening the appellant had gone out of his house for work. The deceased (his father) and his elder brother, Dipankar Baidya (the appellant) were at home. At around 10.30 P.M., when the complainant was returning home he was informed by his neighbour one Utpal Sarkar that the appellant has struck his father with an axe and as a result, thereof his father had succumbed to injuries. On reaching home, the complainant, found his father bleeding and lying in the room. The complainant also found the appellant with an axe in his hand. It was also stated in the complaint that for the last few days the appellant had been undergoing mental treatment.

3. Upon receipt of the complaint, the police investigated the case and submitted a charge sheet against the appellant. The case was committed to the Court of Sessions and thereafter transferred to the Additional Sessions Court for Trial and disposal. Subsequently, charges were framed under S.302 of the IPC. The appellant pleaded not guilty and claimed to be tried.

4. In the course of the trial, the prosecution examined 12 witnesses. The defence did not produce any evidence. The accused was examined under S.313 of the Cr.P.C. but declined to examine any witness in defence. In conclusion of the trial, by a judgment and order dated 20 March, 2009 and 23 March, 2009, the Trial Judge convicted and sentenced the appellant as morefully stated hereinabove.

5. Hence the present appeal.

6. Mr. Tapan Duttagupta Advocate appearing for the appellant strenuously argued that in convicting the appellant the Trial Court committed errors both in law and pertaining to the facts of the instant case. He argued that there was evidence which would substantiate the fact that the appellant was of unsound mind and the defence under S.84 of the IPC was squarely applicable to him. He relied on the decision reported in 2006 (1) Calcutta Law Journal page 342 ( Kamala Bhuniya vs. State of West Bengal ) and the decision reported in 2007 (1) C.Cr.LR 550 ( Sujit Manna vs. State of West Bengal ). He submitted that in a case where the plea has been taken on behalf of the accused under S.84 of the IPC, the court must examine with reference to the facts and evidence whether the prosecution at the initial stage had discharged the burden to establish that the accused person was capable of understanding and appreciating the acts done by him. It was the obligation of the prosecution to show there was mens rea of the accused and only when the prosecution had discharged the initial burden would the accused be called upon to improbalize the prosecution case. He further argued that the investigating agency was duty bound to ascertain the mental condition of the accused person and whether he was mentally capable of understanding the impact of the wrongful act done by him. He placed reliance on the evidence of Bishnupada Baidya being the complainant (PW - 1) to show that he had clearly stated that his