Actually, he DID insert himself into the case but he did not do it immediately as he had to dispose of a body first. He was more focused on moving Jacob around IMO than any investigation. Once the heat was off, he disposed of Jacob and then kept his normal routine. When the cops started looking at him again, THEN he went to interviews and the media to help find Jacob. I think DR gets a kick out of the attention. I believe he knows how smart he has been and enjoys rubbing it in LE's face as to how he has outsmarted them...he kept all the news clippings, pictures and videos, typical of a guilty person.
Too lazy to look but he has his list of unusual things he saw that day. Things he is not revealing to the public because he does not want to scare the perp away.
He has stated in his own way, I feel, that he knows things but LE is just not listening to him.
Maybe later I will look for those quotes.
To me, he comes off as thinking LE is really stupid.