Last year, alarming headlines began streaming into the global news cycle alleging that mass incarceration of Muslims was under way in China's Xinjiang province.
Reports of large numbers of Uighurs and other Turkic minorities disappearing into "re-education camps" had been circulating for a year or so prior, but difficulties in substantiating those allegations on the ground had kept the story well below the radar.
The source of long-running separatist sentiment and allegedly several incidents of violent "extremism", Xinjiang is a region under constant and extensive surveillance. Reporters are routinely harassed by the authorities, while Uighur sources have been known to simply disappear after talking to foreigners.
As a result, much of the evidence reporters have relied on has come from outside Xinjiang, and outside the journalistic field altogether - specifically, it has come from a small handful of independent researchers using methods defined as "open-source".
Used for investigating events such as drone attacks in Yemen and chemical weapons attacks in Syria, "open-source" is shorthand for the software and sources available to pretty much anyone with an internet connection. For those researching Xinjiang's camps, you can add the ability to read Mandarin.
Adrian Zenz, a German academic, is at the forefront of that effort. Speaking to The Listening Post's Daniel Turi near his home in the suburbs of Stuttgart, Zenz explains how, using the Chinese search-engine Baidu, he was able to unearth government documents that proved the existence of China's "internment programme", which officials in Beijing were denying.
"A key search term for this research was the Chinese word jiaoyu zhuanhua," says Zenz, "which literally means 'transformation through education'. When I put in the search term I found all kinds of government documents that very freely talked about transformation through education."
Chinese bureaucrats had left the evidence in plain sight, with government departments uploading official documents - including the policy's legal basis - onto the internet, seemingly without realising their incriminating nature.
The documents showed that China was indeed pursuing a policy of mass detention. But proving the camps were actually being built - enough of them to hold hundreds of thousands of people - required another "open-source" tool.
Shawn Zhang, a Chinese law student at the University of British Columbia in Vancouver, Canada, was one of the first to realise the potential of satellite imagery to reveal the location and size of specific camps.
"I found lots of information, including government tender notices inviting companies to build the camps, and those included the addresses of almost a hundred of them. So I searched them on Google Earth and found the satellite images."
The next step, Zhang explains, was verification: "I needed to verify that these facilities were, in fact, re-education camps. On the satellite images, the re-education camp facilities look very different from civilian facilities. For example, their fences are much higher, and they contain structures used for detention, such as barbed wire and watchtowers. I was able to confirm that these facilities are indeed re-education camps, and so I published my findings on my blog."
The research by Zhang, Zenz and other "open-source" researchers has been integral to major news outlets reporting on Xinjiang, supplying journalists with the hard evidence - not to mention images - they needed to disprove the denials coming out of Beijing.
For Shawn Zhang, however, his status as a Chinese citizen means publishing his findings comes at a price.
"During my research, I have felt a lot of pressure from the Chinese government," Zhang said. "For example, they have contacted my family in China. So in the near future, I think I will avoid travelling to China because the Chinese government is not really happy about people telling truths that they don't want us to tell."
It is a price, however, that he insists is worth paying: "I think it is worth it because there are so many Uighur people held there. They just totally vanished, they disappear, like going into a black hole. They've lost contact with their families. At least my research can help international society to pressure the Chinese government so there can be a better chance of a peaceful solution."
Shawn Zhang - law student, University of British Columbia
Adrian Zenz - independent researcher
James Palmer - deputy editor, Foreign Policy
Yuan Yang - Beijing correspondent, Financial Times