Jiraiya always knew what is Akatsuki up to. He was always saying that he had "reliable source in Akatsuki." So my question is if it could be Itachi. Because who else could it be? Tobi said "Itachi join to Akatsuki as spy" "He joined organization that threatened his village." These quotes indicate that he might be after all source in Akatsuki cause no other had better access to information than Itachi. But I doubt that Jiraiya knew who the source is, and also he didn't knew truth about Itachi, so why would believe him? But what if he was anonymous? Someone could argue that he obtained information by himself, but let's be clear even Jiraiya, who is really good at gaining info and spying and infiltration. I doubt he could spy/infiltrate/gain information from Akatsuki by himself. In Akatsuki, there are S-class criminals and Pain - so they would find out really soon about someone.