New research from The Australian National University (ANU) has unearthed evidence strongly suggesting that Chinese surgeons at state-run civilian and military hospitals have executed death-row prisoners and prisoners of conscience by removing their hearts.
The authors of the study say this practice has been going on for more than three decades.
The study, published in the American Journal of Transplantation, argues surgeons were enlisted by the state to kill prisoners using organ transplant surgery.
According to official Chinese records, the prisoners were supposedly brain dead - a classification given to someone who will never regain consciousness or start breathing on their own again without a ventilator - prior to the surgeries taking place. But the researchers argue, based on their findings, that this can't possibly be the case.
Study co-author PhD researcher Matthew Robertson argues Chinese state and military affiliated hospitals chose to execute prisoners in this manner because organ harvesting is extremely profitable - a claim also made by other human rights researchers.
The surgeries were conducted on death-row prisoners, as well as prisoners of conscience - people who are imprisoned for who they are or what they believe in.
"While we don't know exactly how these prisoners end up on the operating table, we can speculate there are multiple troubling scenarios as to how this happens," Mr Robertson said.
"These include a bullet to the prisoner's head before being immediately rushed to hospital, or a drug injection that paralyses the prisoner."
The researchers argue their findings show the process of execution appears to have transitioned from a firing squad in a field to the operating room itself. Mr Robertson said the removal of the heart is what killed the prisoners.
"We found that the physicians became the executioners on behalf of the state, and that the method of execution was heart removal," Mr Robertson said.
"These surgeries are highly profitable for the doctors and hospitals that engage in them."
The researchers say the operations were unethical because they breached the dead donor rule, which states that organ procurement must not commence until the donor is formally pronounced dead and that procurement of organs must not cause the death of the donor.
The researchers conducted a forensic reading of hundreds of Chinese-language medical texts. They argue these texts show donors had not been properly pronounced brain dead prior to the surgeries taking place.
The main criterion doctors use to determine brain death is whether the patient can breathe without the need for a ventilator.
By closely examining the medical texts, Mr Robertson and his co-author Dr Jacob Lavee, an Israeli cardiac transplant surgeon, were able to determine, in many instances, that the declaration of brain death took place before the donor's breathing ability was assessed using a ventilator.
In other cases in which donors were ventilated, this was done using a face mask and not by inserting a tube into the patients' windpipe (otherwise known as intubation). The researchers say ventilating the patients using a face mask and not intubation is a clear breach of the dead donor rule.
"This was one of the strongest pieces of evidence of failure to adhere to the dead donor rule because ventilation via intubation is a key step in being able to diagnose brain death," Dr Lavee said.
"There were several other problematic features of these clinical case reports. For instance, the donors did not have intravenous lines established until moments before surgery, and several papers referred to acute brain death.
"This evidence suggests that the donors' organs were procured before they could have been properly diagnosed as brain dead."
Mr Robertson and Dr Lavee's findings have been reviewed by Professor Arthur Caplan, Head of the Division of Medical Ethics at New York University's (NYU) Grossman School of Medicine.
"The volume of transplants done [in China] is not consistent with voluntary donation rates," Professor Caplan said.
"This careful review provides incontrovertible proof that health care personnel have been involved in obtaining and transplanting vital organs from individuals who did not meet the criteria for declaring them dead.
"Organ removal has been, as this study shows, the cause of death for some where transplants occurred.
"This abhorrent conduct is a grievous violation of medical ethics, human rights and basic human dignity. Killing for parts cannot be accepted as a part of the field of transplantation by governments, NGOs, health care providers, scientific journals or the general public.
"The evidence is plain and I hope the requisite action will follow."
To carry out the research, Mr Robertson wrote code to download and analyse 124,770 medical papers from official Chinese databases between 1980 and 2020. Using a custom algorithm that scanned the reports, the researchers were able to uncover "clear signs" of unethical conduct.
The researchers found 71 medical publications where heart removal appeared to be the cause of the prisoners' deaths, although they suspect the actual number of prisoners killed as a result of these unethical surgeries is much higher. Fifty-six hospitals and more than 300 medical workers across China were found to be involved.
"Despite condemnation by medical and political authorities across the world, our research is the first comprehensive study that illustrates the active role that transplant physicians in China played in this process, which contradicts the most basic medical ethical rule of first doing no harm," Mr Robertson said.
It's unknown how many prisoners were killed during the transplant surgeries.
Dr Lavee, who spearheaded ethical reforms to end organ trafficking in Israel, said: "Our research exposes the active role Chinese physicians have been taking in executing their prisoners-turn-organ donors.
"As a physician, a transplant surgeon, and the son of a Holocaust survivor, I find it impossible to understand how fellow physicians could take part in such atrocities.
"I hope that our findings will resonate around the world and help bring these practices to a complete halt."