It is difficult to secure a human heart for transplantation. The donor is usually brain dead and on life support, and the donor and recipient must share matching blood and tissue types to prevent rejection.

So Jacob Lavee, a heart transplant surgeon at Sheba Medical Center, Tel Aviv University,  found it hard to believe when a patient in his hospital department in Israel said that he was due in China in a fortnight, on a specific date, for a heart transplant.

“I looked at him and I said: ‘Do you listen to yourself? How can they schedule a heart transplant ahead of time two weeks?’” Dr. Lavee responded.

That was in 2005. Dr. Lavee recounts the episode in the documentary “Hard to Believe,” the first sustained examination of why the Chinese communist regime’s practice of harvesting the organs of prisoners of conscience—what researchers call a mass murder of at least tens of thousands of victims—is not more widely known.

The documentary, which features interviews with medical professionals, practitioners of the persecuted Chinese spiritual discipline Falun Gong, a United States congressman, and others, is now broadcasting on PBS stations across the country.

The film was released on DVD on Sept. 29, and will be made available digitally in the United States for one week only.

The Good Doctor

For some time Dr. Lavee was aware that Israelis frequented China for kidney transplants—but he always presumed that poor Chinese villagers were the donors. This is itself a highly problematic ethical scenario—but humans can live with one kidney.

Heart donations are an entirely different matter. China was known for using organs from executed criminals, but Dr. Lavee noted that the transplant and execution numbers didn’t tally up.

After doing some research into the source of organ donors in China, he stumbled upon a report written by a Canadian human rights lawyer and a former politician, who investigated allegations of organ harvesting from prisoners of conscience in China—specifically, practitioners of Falun Gong, a spiritual discipline which has been persecuted in its homeland since 1999.

“The new information makes absolute sense,” Dr. Lavee says in the documentary, having become one of the key players in the narrative through his own efforts to limit Israel’s involvement in the activity.

The documentary explores how and why researchers believe it’s clear that mass harvesting of Falun Gong prisoners takes place in China, and seeks to understand why more attention isn’t being paid to the matter—why it’s so “hard to believe,” in the words of Louisa Greve, a vice president of the National Endowment for Democracy, who appears briefly in the film.

Tracing a Blood-soaked Trail

One answer can be found simply in the nature of the alleged crime: that the government of China catalogs and extracts organs from its own citizens in a systematic and brutally efficient manner for sale to wealthy Chinese and transplant tourists.

The victims of this organ harvesting trade include Uyghurs, and maybe even Tibetans, though most extensive harvesting was carried out against Falun Gong.

On July 20, 1999, former Communist Party leader Jiang Zemin launched a sweeping national persecution of Falun Gong, a traditional Chinese meditation exercise that incorporates teachings of truthfulness, compassion, and tolerance.