So here is what sets the price of oil. You take all the oil people are buying today. Start at the end of the spectrum, where oil is cheapest to produce, and work your way up until you've satisfied all that demand. That last barrel you need, the most expensive one someone is willing to buy, that's the one that sets the global price for oil. If you're looking for someone who is setting the price, you look for someone who is just about to turn an oil well off or on.
In their case, they had bought oil from a Kansas pastor named Jason Bruns who had just decided to shut down a well on his property.