
Knot Forensics - kposehn
https://www.atlasobscura.com/articles/knot-forensics
======
olliej
Ok, so has anyone done blind testing of this? Because "forensic science" is
already full of snake oil and deliberately ignored bad science. Is this any
different? He's one of the "few experts", is that because this science is new?
or is it because it's not science?

~~~
LargeWu
Nobody claimed it was science; it's just advanced pattern matching. I think
it's very doubtful somebody would be convicted on the basis of this analysis
alone. It seems like it's more useful as an investigative tool rather than
something you can present as evidence in a trial.

~~~
philipodonnell
He basically said "the butcher did it" and the guy immediately confessed.
Certainly it didn't have to hold up in court in this case. :-)

~~~
ken
The article doesn't say "immediately", and false confessions do occur,
unfortunately.

I hope you're right, that it's just one tool to help direct an investigation,
and that the confession was true, but I'm not entirely convinced by this
article.

It starts by claiming he can tell "whether the knot-tier was left- or right
handed, skilled or novice at knot tying, and in some cases, whether the crime
was premeditated", but only a couple specific stories are given, and one was a
knot which "people wouldn’t know of outside of the butcher trade", which is
much more obvious and grounded than the earlier claims.

Of the first 14 Google Image results for "square knot" (before it starts
returning other things), 8 tie it one way, and 6 tie it the other way -- and
as I scroll down, this ratio seems pretty consistent. He claims for a right-
handed person "the knot will almost certainly be formed right handed", but at
first glance it seems much closer to 50/50.

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dsfyu404ed
So where is the quantitative proof that this is better than hair analysis and
bike mark analysis?

Those shams were marketed in much the same way the article makes claims about
forensic knot analysis. Why should we believe in the effectiveness of this
method if the last bunch worked so poorly?

~~~
philipodonnell
There is a very specific claim here that doesn't really need to be shown with
quantitative analysis if he's truly a knot expert.

In the Michigan example, he noted that the knot used was one that only a
butcher would use and that the other guy was a mechanic. Presumably he knows a
lot about knots, and he would know what kinds of knots were common across
different occupations because knots have specific uses, and he probably knows
the few knots that a mechanic uses and a few that a butcher uses and pointed
it out.

There's no need to conclusively prove that a certain person can be shown to
have tied a knot to buy his claims. Only that in cases where one accused is in
an occupation that has a distinguishably common/uncommon knot ratio compared
to another occupation with a different distinguishably common/uncommon knot
ratio, that the information about which knot was used used can, well,
distinguish between the occupations.

Plus, he basically said "the butcher did it" and the guy immediately
confessed, its not like it help up in court.

~~~
monocasa
> Plus, he basically said "the butcher did it" and the guy immediately
> confessed, its not like it help up in court.

Because it's not like we have a problem in the US with people pleading guilty
to crimes they didn't commit when faced against bullish prosecutors with
specious forensic 'science' backing them up, and overworked public defenders
who have to much of a workload to prove to every jury that CSI is fiction.

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msvan
I was hoping to see an application of knot theory
([https://en.wikipedia.org/wiki/Knot_theory](https://en.wikipedia.org/wiki/Knot_theory))
to forensics. Bummer.

~~~
tritium
Meanwhile the article links to [https://www.igkt.net](https://www.igkt.net),
which I'm sure, must have some members interested in topology, as applicable
to knot tying.

