Court caseAIR 1964 SC 1563

The accused stabbed his wife Kalavati to death at night in their house with a knife, inflicting many wounds, shortly after she had come to live with him. He pleaded that he was insane at the time. The defence relied on his conduct and on evidence of earlier mental illness; the prosecution pointed to his behaviour before and after the act. He was convicted of murder and the High Court affirmed.

Subba Rao J laid down the rules: (1) the prosecution must prove the offence, including the mens rea, beyond reasonable doubt; (2) there is a presumption of sanity, and under s. 105 of the Evidence Act the burden of proving the exception in s. 84 is on the accused, but it is discharged on a preponderance of probability, like a civil case; (3) even if the accused fails to prove insanity, the evidence he places may raise a reasonable doubt about the mens rea, and then he is entitled to acquittal. The court must consider the whole evidence of conduct before, at the time of and after the act. On the facts the plea failed and the conviction was upheld.