Cecil the lion’s death at the hands of an American dentist last month was not an isolated incident.

According to a new documentary called Blood Lions, foreign hunters kill two to three lions every day in South Africa. Unlike Cecil, however, these aren’t wild lions. They are captive cats, born and bred in cages solely for the purpose of selling them for “canned hunts”—excursions in small, walled-in encampments where hunters can easily shoot the semi-tame animals without having to stalk them across the savanna.

Prices for these canned hunts start at about $17,500 and go as high as $50,000. Hunters get to take the heads and skins home, while many of the bones reportedly make their way to China and other countries for use in traditional Asian medicine.

Blood Lions follows South African conservationist Ian Michler and American hunter Rick Swazey as they investigate the trade, getting rare footage of crowded breeding facilities and putting their lives on the line as dealers threaten to shoot them for trespassing.

The film has earned praise from conservation groups. “Blood Lions is perhaps the most in-depth and significant look inside the insidious world of South African canned hunts,” said Adam Roberts, chief executive of Born Free USA. (The Born Free Foundation provided funding for the film.) “It shows how nefarious these operators are and visually depicts the massive cruelty of canned lion hunting in grotesque detail.”

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Like Walter Palmer, the Minnesota dentist and big game hunter who killed Cecil, most hunters who pay to shoot captive lions come from the United States. Born Free recently analyzed legal lion exports from South Africa and found that 5,000 of 8,318 lion trophies exported between 2000 and 2013 were sent to the U.S. “That means that roughly three out of every five lion trophies were imported into the United States,” Roberts said. Watch the trailer for the film below.

The American portion of the trade has increased in recent years. In 2013, Born Free found that 84 percent of lion trophies were sent to the U.S.

Although official counts of the number of lions in captivity in South Africa are not available, the documentary estimates that between 6,000 and 8,000 big cats live in breeding facilities, waiting to be shot. South Africa officially labels them “education and conservation facilities.” Michler, however, told National Geographic that these cats could never be released into the wild because they are too acclimated to humans.

Roberts, meanwhile, said the legal trade of lion parts from canned hunts hurts wild populations and “can potentially mask an illegal trade of wild, poached lions.” He noted that the growing lion bone trade—which has emerged over the past few years to replace the flow of products from tigers, which are even more endangered than lions—places additional demand on wild and captive lions.

The filmmakers have said they hope the documentary will expose the lion trophy-hunting industry and shame South Africa into shutting it down.

Blood Lions premiered at the Durban International Film Festival in last month and will screen throughout South Africa starting Aug. 14. International and U.S. distribution is in the works.