Watched it last night.
My partner said the son got on his nerves, but I (kind of) understood him.
For some adoptees they are happy to not look back and find out more about their biological parents. For others though it can become very important. We are all different in how we react to things after all.
Imagine finding out what he did as an adult, and then add to that the fact the woman was the victim in one of the most notorious murder mysteries of recent times. I would probably have been the same as I love a challenge and which is probably why I will research to the nth degree when I'm doing my family history.
If you haven't been raised by biological parents (as I wasn't) then it does allow you a sense of control and "ownership" of a relationship that was never allowed to form in the normal way, when you pursue information about them.
Couple that with a sense that you are here to fight for them. That's a powerful combination.
Having said that it was clear that he needs some closure over the whole thing, but he needs to step back now.
Thought it quite sad really, and showed how the ripples of things years ago still impact. Not just with the son, but others too.