Season 2 question

It seems like there is no specific reason why Jack starts believing Hannibal is the Chesapeake Ripper.

I guess the closest explanation is that when Will is shown to be innocent and is released, Jack would start believing in Will's claims about Hannibal.

But still, Chilton is subsequently "shown" to be the Chesapeake Ripper, incl. by Miriam.

Why/when/how does Jack and later Alana realize that Hannibal is the Ripper? It seems there is no clear reason.