It's probably difficult to find out (but someone here could probably analyze the blockchain), but it would be interesting to know the mean and median stake of the investors who got wiped out.
If the mean is large, it's mostly an off-the-books bribery scheme. If the average stake is small, it's mostly a pump-and-dump con of regular people.
But it was probably just a gambling scheme with just one big bet, where as ever, the house always wins.