If he wanted to do research, all he ever had to do was go talk to the police, or the anti child porn teams...they would have given him every possible cooperation, briefings, organised for him to talk to enforcement officers, shown him, or talked to him about, past cases.
Possession of, and distribution of, child pornography makes him just another paedophile..far as I am concerned, throw him in jail and forget there ever was a key.