How to appreciate evidence if suicide letter written by accused was recovered from body of deceased?

[Educator]

The underlying principle deducible from the observations extracted above is that though it is not impermissible to base a finding with regard to authorship of a document solely on the opinion of a handwriting expert but, as a Rule of prudence, because of imperfect nature of the science of identification of handwriting and its accepted fallibility, such opinion has to be relied with caution and