There were high number billions of dollars in suspicious unclaimed shorts placed just before the 9/11 attacks. Word leaked that the SEC had been called in to investigate whether someone had used foreknowledge of the attacks to make bets on the stock market that would have been huge winners, tipping off any potential conspirators. The options expired without being used, which added suspicion that someone wealthy and connected was in on the attacks. I thought the trail hit a dead end with a brokerage in mideast, but if there were any evidence left, financial software with a long archive could hold it. OTOH, This is the kind of thing you'd expect from a kook.

I think this is a wait and see kind of story. I hope there's more followup.