Todd Spangler NY Digital EditorIn the latest turn of Elon Musk’s will-he-or-won’t-he Twitter buyout saga, the billionaire is demanding hard proof of the social network’s assertion that less than 5% of its users are fake accounts or spam bots — and he said the deal cannot “move forward” until Twitter does so.Without citing any evidence for his claim, Musk tweeted that Twitter’s base could represent “20% fake/spam accounts,” four times what the company claims, and it “could be *much* higher.” He cited Twitter CEO Parag Agrawal’s reply Monday to Musk’s assertion about the fake/spam accounts, in which Agrawal said in part that “Unfortunately, we don’t believe that this specific estimation can be performed externally, given the critical need to use both public and private information (which we can’t share).” “My offer was based on Twitter’s SEC filings being accurate. Yesterday, Twitter’s CEO publicly refused to show proof of <5%.