Also, how do you even validate something like this beyond a reasonable doubt? I saw no actual proof of the verifications of their documents, and it was basically "these are real and I checked. Trust me, I'm the BBC." Was it accidentally sent to the BBC by a gov.cn email or something? If someone just showed up with these documents (which they did, twice removed mind you) how do you know they didn't just create them? Because they're extremely easy to fabricate, just open up Microsoft Word, and someone with even moderate computer forensics knowledge can pretty easily forge all kinds of metadata and other tidbits that makes a fake document seem authentic, even under close scrutiny, because you're ultimately trusting what the file self reports itself to be from. And obviously a piece of paper is even easier in this regard.

So, what? They have a few out of context images of Chinese police, testimonials (which are unnamed and highly aggregated, literally no more than "there are people who confirmed these mugshots are of their missing relatives", the definition of hearsay) saying the mug shots are real, and some censored phone and ID numbers of police (so YOU can't verify it) that if real, probably weren't classified to begin with (why would you classify who's a police officer and who isn't?) And it's not like people, including the police, don't get their phone numbers leaked to the public all the time.

This is a huge issue with leaked documents in general, and there have been plenty of very convincing leaks that ended up being fake. And it's also why in court trials, where authenticity is absolutely imperative, written documents or computer files that weren't obtained by a court discovery order or subpoena is extremely hard to actually get entered into evidence, even if you claim that you took it right out of the murderer's hands. There are chain of custody problems because the history of the document is hard to verify, and it's almost always inadmissible as hearsay (Legal Eagle on YouTube has some good explanations of this).