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Comment by 40four | Hacker News Reader

I don’t get it. I’m mostly very skeptical of the claim of making a positive fingerprint ID through a picture. Has anyone ever heard of this before? Fingerprints are known to be very unreliable and subjective. I’m not convinced this is actually what happened, and not just a cute story pushed by the British law enforcement.

Edit: I did find a couple articles talking about technique of lifting prints from photographs, so I guess it’s a thing? Enough confidence for them to track him down, and win a guilty plea.

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Yeah, the article title should be "Drug dealer caught by online photo that revealed fingerprints". That's the interesting and unexpected part, here. I didn't really know that could be done and hadn't heard of it before; but I suppose it's not too surprising given the prevalence of high-resolution phone cameras, now.

I'm guessing what happened was that they were monitoring an anonymous chat group on this EncroChat app and weren't sure of the true identities of some of the people in it. They saw one of them posted a photo showing fingertips, decided to see if they could extract and match the fingerprints against their database, and got a hit.

I disagree with the (current) top post in this thread saying it's "likely parallel construction". It could be, but the claimed story also sounds pretty plausible, if it's indeed true that they could match the fingerprints based on that photo.

That said, if they didn't heavily downscale or obfuscate the photo before uploading it, the fingertips look so blurry that I imagine it'd be hard to get anything actually useful from it... (https://ichef.bbci.co.uk/news/976/cpsprodpb/F8F6/production/...). If that's close to the original photo, I would grant more probability to the parallel construction/source protection hypothesis.

I'd be quite impressed if the photo was really that blurry and they still managed to extract fingerprints. Though, maybe it could become more feasible with some Photoshop adjustments?

That's not the full image. The full image (https://twitter.com/MerseyPolice/status/1395783747115618306) has a lot of detail in the palm area - enough to get a match I'd assume, if they have his full palm print on file.

Even if it's not a super high probability match, it could have been enough to give them a name and find more evidence.

I don't buy that they'd make up the story _and then tweet proudly about it_, especially when the image they posted is so easy to be sceptical about because of the blur.

Thanks; makes sense.

>I disagree with the (current) top post in this thread saying it's "likely parallel construction". It could be, but the claimed story also sounds pretty plausible

Others have pointed out that this happened in the UK, so it's probably not parallel construction anyways. Still, I wanted to get this out there: isn't the claimed story being plausible a pretty important part of parallel construction? If you needed parallel construction for your evidence to not be thrown out of court, then if the story of how you obtained it isn't plausible, it seems likely that it'll get thrown out anyways.

>Others have pointed out that this happened in the UK, so it's probably not parallel construction anyways.

Yeah, I should've said "parallel construction / source protection / cover story". Parallel construction implies hiding an illicit and/or unethical technique (like warrantless NSA collection methods), but it could also be done to protect a valid information source, like a confidential informant.

>Still, I wanted to get this out there: isn't the claimed story being plausible a pretty important part of parallel construction? If you needed parallel construction for your evidence to not be thrown out of court, then if the story of how you obtained it isn't plausible, it seems likely that it'll get thrown out anyways.

Absolutely. But it's kind of a double-bind sort of situation. If it seems potentially implausible, you can say it smells like a cover story diversion. If it seems plausible, you can say it could be a believable-sounding cover story diversion that's tricked the naive masses.

It's similar to the logic serial conspiracy theorists use; counter-claims are easily dismissed as "that's what they want you to think" / "of course they'd do that". The onus is on the claim-maker to provide evidence of possible deceit.

I support this line of thinking.

It's delusional to completely outsource the assessment of plausibility, it's a fast track to dictatorship. It's on each of us to assess how much faith to hold in such claims. Otherwise we fall into the trap of believing the powers whatever they do.

  - Look, that show trial in the USSR (or Nazi Germany, etc) has concluded with the confessions of guilt from all the accused.
  - But there was no solid evidence presented, there is quite some ground to believe they were forced to confess under tortures.
  - *If they needed* tortures for the confessions in the court, *then if their story isn't plausible, it seems likely that it'll get thrown out anyways.*
  - ???

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