Beyond This Place; by A. J. Cronin,

A young man who discovered that his mother is in fact not a widow, she pretended to be one so her son could grow with no trauma. and that his father is serving for life for murder - and he knows in his heart that it could not be true, and sets out to find what is an old case but not quite forgotten in the small town where it happened, where his father is imprisoned nearby.

His father did always protest his innocence, and had no way of proving his innocence, but was a less powerful person than those that could and did not help. The son however has determination and a fresh youth on his side.

This is only an introduction - no way to sum up the writing of Cronin.