Of course, people change with time and many other circumstances. If he became famous, it can set his feet above the ground.
What happens is that what he did was too much awful. If he already had these impulse and he believes himself overpowered, he even mainly could find a justification to tell himself that what he was doing was good or even a help for the kids.
I love studying human behaviour, that’s why I was so curious about your teacher and what could moves him to act like that.
I don’t either like how much corruption came to religions. It seems the most weak souls or with less conscience are the ones who are arriving to move the leads of most institutions, including the religious ones.