Here is how the short selling scheme works:
stock prices are set by traders called “market makers,” whose job is to match buyers with sellers. Short sellers willing to sell at the market price are matched with the highest buy orders first, but if sales volume is large, they wind up matched with the bargain-basement bidders, bringing the overall price down. Price is set by supply and demand, and when the supply of stocks available for sale is artificially high, the price drops. When the bear raiders are successful, they are able to buy back the stock to cover their short sales at a price that is artificially low.