Columbo does quite often say'that doesn't count what counts is.....'
The commisoner had it in mind all the time that he was going to somehow get his hands on his wife's money somehow.The fact that Hugh Cauldwell killed his wife just seemed to have brought his plans into play sooner than he had expected.Hugh Cauldwells confession would have sealed the commisoners fate then, but now perhaps he would have got off. Even the confession would have been treated quite differently now.