
Police extracted fingerprints from WhatsApp photos to convict drug dealers - artsandsci
https://bgr.com/2018/04/16/fingerprints-in-photos-police-whatsapp-pictures/
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JosephRedfern
(FYI, this was posted yesterady -- there were some interesting comments:
[https://news.ycombinator.com/item?id=16842414](https://news.ycombinator.com/item?id=16842414))

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robterrell
I guess law enforcement doesn't pay attention to stuff like this:

"A new American Association for the Advancement of Science (AAAS) working
group report on the quality of latent fingerprint analysis says that courtroom
testimony and reports stating or even implying that fingerprints collected
from a crime scene belong to a single person are indefensible and lack
scientific foundation."

[https://www.cmu.edu/dietrich/news/news-
stories/2017/october/...](https://www.cmu.edu/dietrich/news/news-
stories/2017/october/aaas-fingerprint-report.html)

~~~
21
You could also have an evil twin brother that you don't know of that might
have committed the crime, thus let's throw out photographic evidence.

Somebody might also put on a fake license plate number matching your own on an
car with the exact model as your own. Thus let's throw out witness accounts of
car type/plate number.

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robterrell
I don't think this is fair. The criticism of fingerprints, as I understand it,
is (a) there's actually no way to prove that "no two people have the same
fingerprints," and (b) the current system of fingerprint classification (using
a few points) could allow different fingerprints to be classified as
identical.

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KirinDave
Sure, but folks using this argument don't quite use "evidence" in the same
sense that courts do. Evidence is not "irrefutably correct", it is "a series
of datapoints that judge (and possibly jury) need to evaluate as part of the
decision."

What's important is to lay out accurate odds for these systems, to which the
fingerprinting folks don't always do. But a 5 point match on a fingerprint IS
information even if it's not wholly conclusive.

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cecilpl2
You are correct in a Bayesian sense, but until everyone is trained to be a
Bayesian reasoner in primary school, we need to build the system in a way that
ensures evidence is considered properly.

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KirinDave
There is much ink spilled about how people aren't bayesian educated, but I
don't really believe it and therefore don't agree with you.

We're actually pretty good at identifying uncertainty and certainty within the
physical world. It's only when we get into very large or very small numbers
that we start to lose the plot.

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wavefunction
Seems like you'd need to prove the pills in question were the alleged
substance?

Just linking a picture of alleged narcotics to someone via their fingerprint
doesn't seem like it should rise to the level of reasonable suspicion. I don't
know what the standards are for the UK though, so I may be applying
assumptions.

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gnode
> Seems like you'd need to prove the pills in question were the alleged
> substance?

That may be true in order to convict him of dealing the ecstacy, but he
wasn't. From the BBC article:

> It [the dealer's house] was raided and large quantities of 'gorilla glue' \-
> a type of cannabis - was recovered.

[http://www.bbc.co.uk/news/uk-wales-43711477](http://www.bbc.co.uk/news/uk-
wales-43711477)

His sentence in the end was for conspiracy to supply cannabis. The suspicion
to search was contextual, given that the image was obtained from another
arrested person (presumably for a drug offence) along with other messages
implying he was dealing to them, such as "what do you want to buy?".

Although I'm not sure how the fingerprint comes into this, given that they
didn't find him by it, but rather "officers had an idea who they believed was
behind the drugs operation", and he was convicted of a different crime, with
evidence from his home search.

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meesterdude
I seriously doubt that photo had enough of the fingerprint in it to get a
match. I'm not saying this can't be done - I just don't see how that
particular photo offers enough data points to uniquely identify someone.

But if anyone has more details on the technical analysis they did, do tell!

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TomK32
At how many points of the finger print they look is a whole different story
and can vary widely.

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gamblor956
Quick heads up to everyone who hasn't apparently read the article: This case
is from the UK, where the evidentiary rules are different. It wouldn't pass
muster in the US as there is an additional procedural hurdle the prosecution
would have to clear to establish that the fingerprint(s) at issue could have
been reliably extracted from the image. If the image in the article is the
actual image in the case, it wouldn't satisfy US guidelines for fingerprint
analysis.

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olskool
Opens the possibility of framing someone by Photoshopping their fingerprint
into a photo.

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test6554
Interesting use of neural networks right there. Putting someone else's
fingerprints on the hand of someone in a photo to make it look like they were
the subject of the photo.

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liquidify
I think I'd be much more concerned about digital fingerprints that come from
the lenses and sensor than physical finger prints. Anyone smart would hide
revealing details. Sites who offer services like this should introduce noise
to the images that distorts at least the digital artifacts.

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anf
Has anyone unlocked a phone using a picture of the owner's finger? That would
be neat!

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gnode
It's not as straightforward as using a printed image; fingerprint readers are
designed to detect only fingers, but it is possible to fool them:

[https://www.theverge.com/2016/7/21/12247370/police-
fingerpri...](https://www.theverge.com/2016/7/21/12247370/police-
fingerprint-3D-printing-unlock-phone-murder)

