...and there is the plain defence of insanity... "it's clear my client was no longer in control of his functions and thus it cannot be proven that he had the mens rea to commit the crime of murder"... provocation could be argued on an obtuse scale, self-defence is a ridiculous claim...
Remember the burden of proof is beyond a reasonable doubt... (unless it's insanity where the onus shifts onto the defendent but the burden is reduced to "balance of probabilities"...)
...and that concludes law 101 children, until next time
