We tracked Ron down St. Lewis and to the hide-out where he was poised and ready to have his memory wiped by redlight. Clarice and I entered the facility and stopped the procedure from happening. I would describe the exact means by which Ron's memories of his time haunted would be removed, but I can't recall for some reason.
The point is, after we freed him of the chair he was strapped to, he went berserk and fled the building, claiming that he had to get away from us before "He took over". We were in enough of a hurry that we didn't bother to capture or kill the redlight present, I'm afraid to say.
We couldn't catch up with Ron again after that, and I'm wondering what this "last option" is. I have a bad feeling about this and we have to find him quickly.