On Thursday, one of the world’s leading specialists on China’s forced organ harvesting business testified before Congress that the Communist Party might be harvesting as many as 50,000 concentration camp victims each year, murdering them to sell their organs.

Each healthy individual killed to extract his or her organs could yield two or three organs, according to Ethan Gutmann, a senior research fellow in China studies at the Victims of Communism Memorial Foundation and co-author of the seminal works on the subject, Bloody Harvest and The Slaughter. This means China could sell as many as 150,000 organs from these victims.

At a hearing held by Rep. Chris Smith (R-NJ), the chair of the Tom Lantos Human Rights Commission, on Thursday, Gutmann appeared with several other experts, including Enver Tohti, an East Turkistan physician who claims to have been compelled to harvest organs from a political prisoner in 1995.

The hearing came after years of evidence that China was killing healthy people in order to sell their organs on the black market to wealthy buyers, the most recent of which was a study published in April by researchers at the Australian National University (ANU) accusing China of execution by heart removal.

In the last half-decade, China has established a network of up to 1,000 concentration camps in occupied East Turkistan, the country’s westernmost area and home to the majority of Uyghurs, using them to torture, indoctrinate, enslave, rape, and kill Uyghurs and other religious and ethnic minorities. Officials in China do not dispute the camps exist, but claim they are vocational training centers where indigenous people Beijing considers to be retrograde learn trade skills in order to compete in the contemporary Chinese economy.

According to testimony given to Congress by concentration camp inmates, China analyzes prisoners to determine whether their organs are suitable for transplantation, and those who pass the test vanish.