The Commodity Futures Trading Commission alleges the speculators bought enormous amounts of actual crude oil for sale in Cushing, Okla, during the early months of 2008.
This created a perceived shortage of oil in Cushing -- a major point for oil delivery -- and drove the price of oil futures contracts higher.
The speculators then bet the price of oil would fall by selling so-called "short" contracts to other investors. When the speculators sold their actual oil holdings in Cushing en mass, the price of oil did fall, netting the group a hefty profit.
CNN Money Watch
If you don't think stuff like this is not happening on a global scale under "legal" conditions you're a fool. A damn fool.