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Comment by bb88 | Hacker News Reader

I'm wondering if the Indiana police train their drug dogs with the scent of cash as well.

The point of K-9 units is to manufacture probable cause. Yes they can “smell” the cash if the handler wants them to.

If this were the case, would someone not have challenged it in court by now? If the dogs and their handlers were challenged in a controlled trial and shown to be biased, that would make for a useful test case.

To do that, dog should be handled by someone who is not their regular police handler. Then they would claim he doesn't know how to handle the dog properly, or doesn't have the required "soul bond" with the animal. Can't win against crooks.

> To do that, dog should be handled by someone who is not their regular police handler.

Not necessarily if the experiment is double blind. (Or tripple blind I guess because it is the dog, the handler and the on-site experimenter who are not aware of where the samples are hidden.)

> Can't win against crooks.

That is the bigger problem.

you are right

Wow questioning policing methods gets you automatically labelled as 'crook'?

How is the boot tasting this morning?

In my reading the parent comment is labeling police as crook's not the GP or anyone for criticizing.

The FBI spent 4 decades grossly lying about their ability to analyze hair. Think about that. The charade actually went on so long that some people would have lived their entire adult life, their entire career lying their asses off. It was later found that at least 90% of cases contained errors.

During this time someone could have similarly proved that it wasn't so because were it so surely someone could have challenged it.

An alternative explanation is that forensic science or indeed any sort of science as practiced by law enforcement has always been a joke and the bar to do something about it is always very very high.

The cost of challenging anything is often prohibitively expensive both in terms of legal costs and in risk of drawing a sentence several times worse than a plea and any case which might result in police losing a valuable tool can be mooted by simply dropping that particular case after that high bar is met.

Remember also that the prosecution and the judge aren't scientists but ARE colleagues. Perceptively evidence from dogs are brought only when they actually find something so even if they don't provably always "work" in the scientific sense they perceptively help them nail bad guys. The idea that the judge would be liable to remove that useful tool because it didn't pass scientific muster is both optimistic and naive.

https://www.fbi.gov/news/press-releases/fbi-testimony-on-mic...

"Handlers were falsely told that two conditions contained a paper marking scent location (human influence). Two conditions contained decoy scents (food/toy) to encourage dog interest in a false location (dog influence). Conditions were (1) control; (2) paper marker; (3) decoy scent; and (4) paper marker at decoy scent. No conditions contained drug or explosive scent; any alerting response was incorrect. A repeated measures analysis of variance was used with search condition as the independent variable and number of alerts as the dependent variable. Additional nonparametric tests compared human and dog influence. There were 225 incorrect responses, with no differences in mean responses across conditions"

"To test this, we influenced handler beliefs and evaluated subsequent handler/dog team performance according to handler-identified alerts. The overwhelming number of incorrect alerts identified across conditions confirms that handler beliefs affect performance."

https://link.springer.com/article/10.1007/s10071-010-0373-2

That just isn’t how it works.

Police science is a parallel world of non-science. Over and over, fake science like hair id, bite mark analysis, fire, shaken baby, excited delirium, and others are debunked. But the courts have been terribly uninterested in hearing science contradict police-science.

To be clear: courts have their own way of deciding disputes, and that process has distinct differences from the scientific model. E.g. stare decisis is actively hostile to new evidence; appeals may not reference new evidence; police practices are given deference as experts in their own magisterium, and may not be held to normal scientific practice; and others.

All contraband dogs are trained to alert on cash.

Sounds plausible, but do you have any sources?

Dogs absolutely can be and are trained to detect cash. A better question might be, what can't dogs be trained to sniff out?

https://www.akc.org/expert-advice/news/meet-currency-detecto...

LSD?

Cocaine and rabbits blood apparently. https://www.statesman.com/story/news/2016/09/24/danish-fishe...

Sound more like the opposite?

  During a three-week period, fishermen fooled the Nazis and police dogs who
  searched their ships – lacing handkerchiefs with a mixture of rabbit blood and
  cocaine, in order to fool the dogs.

That kind of seems like the mixture of rabbit blood and cocaine overwhelms other scents?

Arf arf officer Buddy has detected traces of potentially terroristic thoughts in your mind racks shotgun unlock your iPhone NOW!

Black pepper ground finely?

From the concept of "they'll only do that once, and probably be useless the rest of the day". ;)

I hadn't heard of this before, but here are some sources. Note this quote from [2], U.S. Customs and Border Protection:

"Canines are taught to detect concealed U.S. currency and firearms. Both the Officer/Agent and canine are taught the proper search sequences when searching vehicles, aircraft, freight, luggage, mail, passengers and premises."

I have no idea what the ratio of scientific backing vs. security theater is, though.

[0] https://www.cbsnews.com/minnesota/news/golden-valleys-new-k-...

[1] https://www.akc.org/expert-advice/news/meet-currency-detecto...

[2] https://www.cbp.gov/border-security/along-us-borders/canine-...

> I have no idea what the ratio of scientific backing vs. security theater is, though.

Yes, dogs give you a convenient excuse to produce 'probable cause' in order to authorise a search whenever you feel like it, because the signs the dogs give are interpreted by their handlers.

So it's not necessarily so much security theatre, as perhaps 'whitewashing' of evidence obtained in other ways. see eg https://en.wikipedia.org/wiki/Parallel_construction

Cannot find the story now but there was situation where they sentenced woman for drug possession ONLY because dog indicated so, but they found no drugs on her or in her car.

Do you happen to remember if she was sentenced because she was convicted by a jury? I have very little faith in the U.S. justice system so I guess that wouldn’t surprise me, but it feels likelier that they used the K9 “evidence” to coerce her into accepting a plea bargain (which, to be clear, is also bad).

Apologies she was not convicted but was jailed - I misremembered and it was rather hard to find but as I see it should be this story:

https://reason.com/2021/05/13/the-police-dog-who-cried-drugs...

The mention of “U.S. currency” raises my suspicions. How does a canine distinguish between U.S. and Mexican or Canadian currency?

Polymer versus paper?

Polymer versus cotton + dyes. US currency has a unique smell to my human nose, even.

Their handler whispers “dinero” or “money, eh” instead of “deutsche mark”.

IDK about Canadian, but even I can tell the difference between USD and EUR/CZK banknotes by smell.

That said, no one on the Internet knows that I am a dog.

But can they detect gold and diamonds?

But…nearly everyone carries or handles some amount of cash. Is a bank teller continually triggering the dogs?

> But…nearly everyone carries or handles some amount of cash

Well, then I guess the handler can usually find probable cause!

Only when the dog handler wants them to!

considering most cash has traces of cocaine on it they probably don't need to train them hard.

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