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Comment by nickysielicki | Hacker News Reader

I don’t understand the argument here. Suppose shotspotter is deeply flawed and often confuses fireworks and car backfires for gunshots, how could that have any impact on this case or the legality of it?

I don’t see it as any different than if a police officer is out patrolling, hears a car backfire, and confuses it for a gunshot. If he then detains someone as a part of his investigation and discovers some other crime, he still has probable cause because it wasn’t unreasonable for him to confuse a loud bang for a gunshot and for him to investigate.

The same holds true for shotspotter, regardless of if it makes mistakes. Even if shotspotter has some bug in their acoustic analysis that identifies loud bangs where there isn’t one, ie: total false positives, so long as it sometimes does detect a real gunshot, the police have probable cause to investigate.

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Imagine I made a magic "crime detection" box that called the police each time a crime was "detected".

Now imagine all it did was randomly pick a number from 1 to 100 each day and if it were a 1 or a 2, it "detected" a crime, giving probable cause to police to search people near the box.

Now imagine I almost exclusively put the boxes in areas where black people without a lot of money lived.

You could see this would be something of a problem, right?

I would have a problem with that, but I don’t think that’s what’s going on here.

My gut feeling is that shotspotter mostly works and is mostly accurate, regardless of what Vice reported. I can imagine how I’d build such a system and I don’t think it would be very complicated. You don’t need any powerful signal processing or AI, this entire idea was feasible 20 years ago.

And secondly, I think that if any technology is rolled out by a city in a way that’s discriminatory, that falls squarely on the city and their police department, not on the technology company that sold it to them.

The problem is not that no one could build a system to detect and triangulate gunshot sounds.

The problem is that this specific company seems to be strong on marketing claims and light on engineering legwork. There have also been some implications that point to (in my opinion) post-indictment editing of records to gin up post-hoc probable cause in some cases. No smoking gun (ugh) to prove it but concerning.

What is known is that ShotSpotter reports seem to rarely create useful leads for police. It would hardly be the first (or second, third, fourth, et al) time someone promised to revolutionize policing only to hand over snake oil. Then when the money faucet begins to dry up some companies just can't help fabricating proof of their technology or even falsifying evidence to make sure police "see the value" in continuing to pay for it. Most police departments are being taken for a ride. Some fully understand the wink-wink-nod-nod going on and appreciate the company's "flexibility".

Your "gut feeling" does not comport with any evidence presented so far. Until SpotShotter is compelled to reveal their techniques and present them to the defense, as the defense is entitled under law, it's just a magic box that conveniently agrees with the police when they want it to.

> My gut feeling is that shotspotter mostly works and is mostly accurate

I don't want to base our legal system on your gut feelings. If ShotSpotter is mostly accurate, then they should have no problem releasing the requested material and proving that's the case.

Otherwise I will have to assume it's just the magic crime detection box as described above.

Word. I detest these kind of posts.

East Palo Alto has shotspotter installed throughout. In summer of 2020 there were several weeks of nightly nearly non stop fireworks. Shotspotter should have been able to help the police pinpoint the locations of these illegal fireworks yet no enforcement actually happened.

Now part of that might be because of the defacto police strike in response to "defund the police", but the noise went on long enough and was heard in nearby wealthy cities enough that actually motivated police forces were pushing to fix the problem and yet shotspotter proved useless.

This leads to the allegation that shotspotter doesn't actually work at all and is just there so when a hothead young cop does something wrong without thinking the police department can, after the fact, get shotspotter to gin up some probable cause.

I would think the system will have difficult time materializing high rates of people that have been shot, which tends to be the chief metric for where it's deployed.

Imagine if there were 100 gun murders in a city in one year and you had a magic box that was 100% accurate at detection of location of gun shots within 1 mile and the city could only afford to buy 10 magic boxes.

Would you put those magic boxes near where previous gun crimes have been committed or would you put those boxes in places based on the race and sexual orientation and disability status and gender of the people living in the city?

Well how useful is that anyway? Probably not useful for evidence or crime prevention. I imagine most murders are known about fairly quickly due to a corpse (except say by “professionals”) or people hear the gunshot and call in.

Logically I would say spending the money on gun control would be better, but politically that seems like a no no. Make carrying in the street illegal with jail time, and use the money in a gun amnesty.

There's no evidence the system is 100% accurate within 1 mile.

To me this is obviously unethical, but wouldn't this also be obviously unconstitutional in the US? At least if done deliberately? 14th amendment and all that.

Assuming the question were to reach the Supreme Court, and not considering the possibilities in the various Circuits, there is a substantial chance all of the Supreme Court’s various composition over the last 50 years would uphold the use.

First consideration would be applicable legal standard, which practically always errs on the side of the State, second is the reasonableness of statistical methodology presenting the locations based on crime statistics.

I would not personally argue for its constitutionality, but given the precedents stemming from pretextual patrolling cases, it isn’t as clear cut as one might hope.

That was very informative, thank you

The magic box already exists, it's called people who call the cops to report gunshots every time they hear fireworks are a car backfiring.

If you think it's wrong for police to investigate a shotspotter alert because it might be a false positive then the logical conclusion of that line of thinking is that it should be illegal for the cops to show up to investigate when someone calls in to report gunshots, since those are mostly false positives too.

I don’t see the logical connection between what the parent comment said and your reply.

He is saying they could be selling pure snake oil, and worse using it for discrimination (but not sure what the basis was for that, if any).

Shotspotter stores the raw audio so you can just ask for the audio and evaluate for yourself whether a reasonable person would identify that as a gunshot.

Either hearing a gunshot is not probable cause to pull someone over (in which case Shotspotter's accuracy and methodology is irrelevant), or hearing a noise that sounds sufficiently like a gunshot is indeed probable cause, in which case you can just listen to the audio yourself and make a determination about whether or not there was a true gunshot-like noise or the company invented a fake alert out of thin air. I don't see any scenario in which the methodology or accuracy of Shotspotter's devices is at all relevant to this case. The relevant fact here is whether this particular bit of audio can be reasonably classified as a gunshot, not the broader accuracy of the system over the whole data set.

"Someone hearing a gunshot" is not probable cause to pull someone over, just as someone calling in a gunshot to the police is not probable cause to pull someone over.

The article isn't clear. The defense claims that the driver was pulled over solely from the shotspotter alert:

>>Attorneys from the Cook County Public Defender Office, contending the police pulled the man over solely based on a ShotSpotter alert, subpoenaed the company as a third party to find out whether that was the case.

but that seems unlikely -- it would be really expensive and low-yield to pull over everyone in the vicinity of a gunshot. It would be about the same as with regular human ears hearing a bang: go to the source, then pull over cars with evidence further differentiating them as a possible locus of crime.

So probably shotspotter got the cop to that location, where he saw other, more crime-specific evidence. But without more info about this case I couldn't say for sure.

> it would be really expensive and low-yield to pull over everyone in the vicinity of a gunshot

Expensive and low-yield for whom? For the officer who's been directed their by the robot, they're incentivized to do so; it makes them look like they're doing their jobs instead of doing nothing. What's built into the system to penalize them for inconveniencing / endangering a bunch of people with nothing to show for it?

Searching a car and catching a criminal always makes them look better than just searching a car. [1]And I’m not sure how your point, if you have one beyond making yourself look smart, relates to the broader issue of whether shotspotter was the only evidence, which was the focus of that comment.

And if you’re economizing on time, I can assure that a better use of it would be to answer the challenge you kept dodging (or “misinterpreting” as a opportunity to show off irrelevant knowledge):

https://news.ycombinator.com/item?id=32259971

At this point I’m just going to assume you have no idea if 7% is a good threshold or not, but still see so problem with shouting it because it sounds good.

[1] In case you forgot, the only reason you were outraged was because the search did catch a criminal that it shouldn’t have. So obviously someone cares about catching a criminal!

Sorry, I'm not sure where you're picking up "outrage" from my comment. You were asserting "It would be really expensive and low-yield to pull over everyone in the vicinity of a gunshot" and I was asking 'for whom?' I don't see how incentives are aligned for that to be expensive at all for the person doing the pulling over, and I tend to evaluate people's behavior on the assumption that, all other things being equal, they'll do what they're most incentivized to in a given situation most of the time.

It's expensive for the community, to be sure, but the cop's not incentivized immediately to care about that.

>Sorry, I'm not sure where you're picking up "outrage" from my comment.

It wasn't in that comment, it was in the premise of all your previous posts that it is outrag^W^W^W^W^W suboptimal for someone to be pulled over and eventually arrested for DUI when the original instigating cause was a false positive for gunfire.

IOW, the entire reason you're talking about this case, is because they did not pull over everyone in the vicinity but prioritized those that were more likely to be committing crime, based on other signals. That's how we got to this case to begin with! And yet, I'm having to remind you that you're arguing with yourself.

Do you consider it too much to ask that you remember the context of what you're talking about? And for others not have to remind you?

Also, thanks for the confirmation that you don't have a substantive answer to the substantive question, "what probability threshold is appropriate for police to enter in preparation for an active shooter" -- I had always assumed your comment was bad-faith to begin with. Especially when you deny that comments such as these are expressing something similar to outrage:

https://news.ycombinator.com/item?id=32259925

Which means that Shotspotter's methodology is irrelevant since there's no probable cause in any case, so the discovery request is unjustified.

If reporting from Shotspotter is presented as evidence, the discovery request is justified.

The article suggests that the police can go to Shotspotter and ask for some other convenient sound or perhaps even no sound at all(?) to be retroactively reclassified as a gunshot where they wanted it to be, so they can then use that as an excuse to stop the person they already wanted to or already did but didn't have a valid reason to. That's worse than random and worse than a policeman honestly mistaking a backfire for a gunshot.

The cop that heard the backfire would likely be called to testify that fact in court. If they fail to show up, and the arresting officer (a different cop) claimed they made a probable-cause traffic stop based on what the other cop heard, and that cop refuses to testify, the prosecution is going to have a bad time.

> ...the prosecution is going to have a bad time.

Probably not. Cop said it, court saw it written, that settles it. Now prove your innocence without the ability to face your accuser. They're a cop, of course they're 100% correct in everything they wrote down, so... yeah, pay your ticket.

I've seen this a few more times than I'm the slightest fan of, for me and other people accused of "impossible things" in cars (like "being clocked far faster than the car is capable of having accelerated to based on where it turned onto the road").

The prosecution has no problems with, "But the cop wrote that they saw you doing 70 in a 35, wrote the ticket for 45, and they're not here, so you're guilty."

A better analogy would be, if you asked the cop how he decides it’s a gun firing vs some other innocuous cause, and his department refused to allow the records of his brain scans to be admitted into evidence to determine if he were perfectly consistent in going after gun-like sounds (assuming it were a department that had brain scans going on for officers on duty).

But that’s a ridiculously non-applicable analogy. Any request for such brain scans would be deemed, at least in almost all conceivable circumstances as over reach by the defense. In reality all the cop has to do is say based on his training and experience he is comfortable in distinguishing the sound of gun fire in a city environment.

The proper analogy is to say that this company is not allowing for the experience and training testimony to be shown to the court. That would be how I would argue against probable cause in this case. However, as another comment in the thread discusses, this is probably not an issue since there is a heavy dose of parallel construction argument going on.

What perplexes me is that in the USA we have a constitutional right to face our accuser in court. But this is a piece of software.

> In one case, a 65-year-old grandfather was held in Cook County Jail for nearly a year at the height of the COVID-19 pandemic before his case was dismissed due to insufficient evidence.

I mean, WTF.

I dug up the story behind that 65 year old grandfather.

https://www.chicagotribune.com/news/criminal-justice/ct-shot...

Prosecutors accuse him of shooting his passenger, but he claims that another car pulled up next to him and shot his passenger instead. In either case shotspotter both correctly identified a gunshot and the location of the gunshot, so what exactly did they do wrong here? By the defendant's own admission the gunshot that triggered the alert was real! Unless crucial details are being omitted somewhere it seems like a hatchet job to me.

Great points. Thanks for doing that research. I should’ve done it myself and I am embarrassed that I did not.

Pretty sure the scenario you described with an actual police officer does not count as probable cause either. You can't just start detaining people because you heard fireworks, even if you mistook it for a gunshot.

If the officer lied about having probable cause (e.g., by telling ShotSpotter to fabricate alerts or to re-classify an alert after a stop to manufacture probable cause), the case can be thrown out.

But we can't know if the officer lied because SpotShotter refuses to reveal how their black box works. Since the officer's word is like unto God's in most courtrooms, the defendant is kinda stuck.

If the police officer was lying about hearing a gunshot to perform an illegal search, or the police officer used the “I heard a gunshot” excuse six times a day, then that would be a problem.

Okay but I don’t think the argument here is that there was no “bang” sound, only that the company with technology for classifying bangs might not be perfectly consistent, which is still a higher burden than applied to a police officer investigating a bang sound.

The problem is at least with police, presumably (and I understand this doesn't functionally work due to the dysfunction of the police & court systems) if the police kills and/or maims an innocent person due to their error, they can be held responsible for their stupid decision.

One of these cases is a class action on behalf of people who have been wrongly arrested because of spotshotter - the case is also trying to get the police to stop using it because of this - if it's wrong most of the time police do not have probable cause - they have improbable cause

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