As I see it, this position is untenable. We are now in a situation where the headmistress of the school is shown to take the side of the person who abuses their position of trust even when faced with a guilty verdict delivered by the court.
To slightly complicate matters the verdict of a court doesn’t determine if someone has or hasn’t done something (as many guilty people who have got off, and innocent people who have been convicted can attest)
So to turn the moral dilemma round, if your wife had been found guilty by a court, but you believed that she hadn’t committed the crime that she had been accused of, what would you do?