New York City police commissioner Bill Bratton, center, speaks during a news conference at police headquarters in New York, Monday, March 16, 2015. Bratton and New York City Mayor Bill de Blasio were talking about ShotSpotter, a new technology that the NYPD is using to detect gunfire throughout New York City. (AP Photo/Seth Wenig)
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In addition to [ShotSpotter’s] history of false positives, the danger it poses to pedestrians and residents, and the company’s dubious record of altering data at the behest of police departments, there is also a civil liberties concern posed by the fact that these microphones intended to detect gunshots can also record human voices.

Yet people in public places—for example, having a quiet conversation on a deserted street—are often entitled to a reasonable expectation of privacy, without overhead microphones unexpectedly recording their conversations. Federal and state eavesdropping statutes (sometimes called wiretapping or interception laws) typically prohibit the recording of private conversations absent consent from at least one person in that conversation.

In at least two criminal trials, prosecutors sought to introduce as evidence audio of voices recorded on acoustic gunshot detection systems. In the California case People v. Johnson, the court admitted it into evidence. In the Massachusetts case Commonwealth v. Denison,  the court did not, ruling that a recording of “oral communication” is prohibited “interception” under the Massachusetts Wiretap Act.

It’s only a matter of time before police and prosecutors’ reliance on ShotSpotter leads to tragic consequences. It’s time for cities to stop using ShotSpotter.

— Matthew Guariglia in It’s Time for Police to Stop Using ShotSpotter


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  1. if i see someone waving a gun around i light off some bottle rockets so the rollers can swing by in an hour.

    • Back in the day before EFI, you could run your carburetor on the rich side and let the neighborhood hear the [pop!] [pop!] [pop!] from the tailpipe.

      The ‘Hood’s old fashioned version of fireworks…

      • Had a few motorcycles in the day where all it took was the clutch to be pulled and a quick full throttle twist and release… and it sounded like a small firefight. One time my buddy and I took the pipes off of my Triumph Legend TT (885cc triple) and started her up… we experienced our own version of “Shock and Awe” right there in the driveway. Gotta love it!

      • I’d pull the choke, turn the ignition off coast a bit then turn the ignition back on. Hard on valves and push rods.

  2. I propose that in New York and Chicago we place a gun control advocate on every street corner to act as shot spotters.

    It will not be long before they will be crying for police protection and guns, and get an introduction to the real world the rest of us live in.

  3. Not too sure about this subject. The street is a “No expectation of privacy ” zone. It allows people to record the police during public interactions. It’s a two way street though. Police wear body cameras in many jurisdictions to keep a record of events. If the SCOTUS says we, the public, can record the police then they can record us including sound I would think.
    I do think the “Shot Spotter” tech is ripe for abuse in that it might be used for probable cause to stop and detain people in an area that a ‘alleged’ sound was made.

    • I believe the distinction is that the police are government employees and you have the right to record them doing their job in public. You have the right to video record me crossing the street. You do not have the right to eavesdrop on the conversation I’m having while walking.

      • “..You do not have the right to eavesdrop on the conversation I’m having while walking…”

        I don’t believe that to be a true statement. The ‘street’ has been determined by the courts to be a “no expectation of privacy” zone so it depends on where you are walking. Private property vs public.

        • While I don’t agree with it the law is that you have no expectation of privacy outside of your home. “People have no reasonable expectation of privacy in public spaces where their actions, possessions can be seen or conversations heard, again whether the content at issue is physical or virtual. Some examples of such places are public sidewalks, venues hosting sporting events and public parks.”

          That being said and is the law backed by a SCOTUS ruling, I am all for ShotSpotter.

          It’s 97.70% accurate in determining gunshots. Large cities need that technology so they can dispatch police accordingly.

          People are worried about being overheard on a public street and yet your TV remote can hear every word you say in your own house if you have voice activated remote.

          Siri, Alexa and all the other gizmos that people use like say a $10 webcam with a microphone for your kids virtual classes all can hear you.

          If you don’t feel like being overheard then don’t say it, write it down.
          Chances are someone is listening, even in your own house.

          Yet people are worried about ShotSpotter on a PUBLIC STREET?

        • It’s one thing to overhear a conversation between two people walking down the street and quite another to record it using a multimillion dollar state of the art recording and sound analysis system.

    • You are correct. The test is whether is if prudent person reasonably believes they have privacy in that particular set of circumstances. In the SCOTUS case an example was entering a phone booth with the door closed.

    • Manse Jolly,
      Amen! It is amazing how today’s “civil libertarians” compromise away essential, long-standing rights with their “nuanced, balanced, realistic” perspective on freedoms explicitly spelled out in the Bill of Rights, yet seethe with fire-and-brimstone fanaticism about made-up, nonexistent, and impossible “rights” like the right to privacy in a public place.

        • Dave,
          I’m not sure what you mean, because Plain View Doctrine (PVD) is essentially what I was describing.

          Unlike many legal doctrines or rulings, it is not a wordgame of lawyerly nuance and abstraction, but the antidote to such things. It basically says “For 4A purposes, ‘Private’ and ‘Public’ mean what the dictionary says they mean, and are opposites. 4A listed things that normally enjoy a reasonable expectation of privacy, and should therefore be secure against warrantless searches, but making the conscious and uncoerced choice to make your private stuff public [by showing or doing it on a public street, for instance] forfeits the claim that it’s ‘private’.”

    • The only reason a person ‘hears’ someone talking is from the vibrations traveling through a medium. It’s the reason you will never hear a gunshot in space.

      Technology is advancing. All it requires is a more sensitive ear. Just like with a satellite in orbit, things change when the resolution of the camera advances to the point of seeing a pimp on someone’s face from a hundred miles up.

    • No, the police can’t just arbitrarily record you because SCOTUS says citizens can. The SCOTUS ruling doesn’t apply to police or government agencies for that purpose.

      • Earlier I lost a lengthy reply..M$ updates grrr….so question, in order to be brief, how many hours of video is the DOJ and Nancy P. sitting on that defendants of Jan 6th want?
        How many cameras are at intersections, depending on population? How many cameras in town parks/spaces and whose watching? Answer=police.

    • Manse Jolly,

      I think the topic is a tiny bit more nuanced than your characterization.

      We do not completely surrender all rights to privacy in public. Public surrender of privacy is limited to the concept that I cannot prevent other people in public from going about their business (e.g. approaching me) in order to preserve my right to privacy. We do retain the right to lower our voices or pause our conversations if we want to maintain our personal privacy when WE SEE SOMEONE IN OUR VICINITY. In other words we still have a right to a reasonable level of privacy in public which does not interfere with other people’s rights to go about their activities in public. That is a simple and pragmatic “rights balancing” solution.

      Let me illustrate the concept with a parallel example. Being in public does not mean that anyone and everyone can surveil me any way and every way that they want: I still have reasonable privacy rights. Thus, a pervert cannot legally install a hidden camera on a public sidewalk in the hopes of capturing images/video of women’s groin area up their skirts as they walk by.

      The key here is that no entity can employ secret surveillance devices because that totally destroys any privacy that we have in public.

      As for recording police in the course of their official duties in public, that is a separate concept from privacy rights. The idea is that we are recording the conduct of government employees carrying out actions in the public interest. By definition that has to be visible to the public and we have to be able to scrutinize those actions for simple accountability reasons. We can also argue that we must be able to record the actions of government employees in public in order to petition government for redress of grievances (regarding government misconduct)–a right guaranteed in the First Amendment of the United States Constitution.

      • Sure it nuanced, just not as you think. I don’t wish to write a book here. So question since you mentioned filming groin areas. Can a naked person on a public street be recorded? Better believe it. Again, there is no expectation of privacy. If I see you urinating on a public street I can record that as well. So can the police and any other agency.
        I can walk right up to you and listen, as long as you’re talking, to everything. Your choice is to move away or stop talking. Heck, I can lip-read from across the street and publish what you say.
        It is the world we live in. Our ‘Rights’ come with a whole lot of exemptions.

        • “In other words we still have a right to a reasonable level of privacy in public which does not interfere with other people’s rights to go about their activities in public. ”

          No, SCOTUS has ruled on this.
          A judge would laugh in your face over your argument.
          There are no nuances, you have NO expectation of privacy outside of your home or abode.

          “The key here is that no entity can employ secret surveillance devices because that totally destroys any privacy that we have in public.”

          Once again YOU Have No Expectation of privacy outside of your home or in PUBLIC. YOU may not like it but it happens a lot more then ShotSpotter.

          Once you step outside your door you can be recorded by any means.
          Through a window in your home? No, you cannot be legally recorded.

          Once you put your garbage out and it’s not on your property anybody can go through it legally. You don’t even have no expectation of privacy with your garbage. The law is very clear on all of this. No nuances.

  4. I remember Troy stopped using the shot spotters they had because the data it produced was obviously too many false positives as a disproportionate proportion were all concentrated around the subsidized housing area. Apparently the hills distorted the sounds and put them in that neighborhood………..

  5. No wonder Big Brother does not want you to have a Silencer. Having so much crime in NY prompts a need to have gizmos to listen for gun fire? Could that crap be NY Gun Control back firing? When criminals know there are laws banning guns like in NY they know the odds are in their favor victims will be unarmed easy pickings.

    The questions for the citizens of NY are…Over the past six plus years what percent of NY victims of crime were unarmed and incapable of self defense? And what agenda that sounds good on paper but has proven itself to be a path to death and destruction is to blame for that? Could it be, “GUN CONTROL?”

      • Depends on the gun and ammo used. Omaha has Shot Spotter close by my house and at least twice I’ve put two critters out of their misery due to one of my Huskies not finishing the job. No police showed up and I’m sure my neighbors were completely unaware I was firing a SS Ruger MKII with a SilencerCo White Sparrow loaded with CCI subs in my backyard.

        • It depends more on where you are.

          You could be firing SS Ruger MKII with a SilencerCo White Sparrow loaded with CCI subs in your back yard but take that same combination someplace else and it may be detected.

          Most everything that moves has a unique sound signature, one of them happens to be bullets being fired (even if using a suppressor)

          For example, all breaking glass actually shatters at the nexus of any multiple cracks and all glass breaking has multiple cracks even if you can’t see them because they are so small and you can’t tell because the shatter point is so small. But when that shatter happens it creates a unique high frequency sound that a person can’t hear but (properly designed quality) glass break detectors with microphones tuned to that can hear the unique sound signature.

          Bullets from weapons fire has a variety of unique sound signatures that happen when the bullet leaves the barrel (or suppressor in this case) even if sub sonic rounds are being used.

          This is the reason that ShotSpotter themselves say that use of suppressors doesn’t prevent detection – because it doesn’t but location and direction will let it be detected even if you are using a supressor. All sound as it travels begins to deflect or be stopped by anything it encounters which decreases the level of the sound and that includes those unique sound signature sounds that you can’t hear. If that level drops below the ShotSpotter detection threshold it does not detect it, but let the slightest bit exceed or touch that detection threshold and it gets detected. Depending on where you are, its a little challenging but the sensors of the Shot Spotter may detect the unique sound signature of a bullet being fired via suppressor even with CCI subs.

          Supressors decrease the explosive/impulse sound of gunfire, but do not completely eliminate it. The bullet still makes those unique sound signature sounds.

        • Jack

          “It depends more on where you are.”

          No shit. That’s why I said I was in Omaha close to Shot Spotter detectors.

          “ The bullet still makes those unique sound signature sounds.”

          Wrong. A suppressor (silencer) suppressed the sound to a level where it was not detected PERIOD. Not only once, but twice.

          If Shot Spotter detected the unique sound signature of a bullet being fired, there would have been a police response.

      • “The ShotSpotter sensors are designed to pick up the sound of gunfire from suppressors, but it does make it more challenging.”

        That’s a really a big but. Obviously shotcrapper did not say specifically the use of suppressors doesn’t prevent detection. Or did they jump up and elaborate on their tests using Silencers. That says taking them for their word on anything when millions of dollars are on the line is not prudent.
        Perhaps if someone used a silencer to shoot the moon in the middle of downtown @ 3:00AM it can (no pun intended) be detected. And according to shotcrapper a staff of listening specialists determine what is what.

        So when the money is spent and the smoke clears and spotcrapper could not locate a silencer shooting the keee jerk solution becomes no silencers for anyone. The entire pdf reads like a script for an infomercial that skims only the surface. The only way to really determine fact from fiction is to buy it.

  6. Meanwhile, the real worry should be about all the ‘smart’ products in your home listening and most likely recording your every word.

    Alexa – your own personal eavesdrop assistant

    Smart phone – you think those cameras, microphones and GPS are not reporting when you switch them to ‘off’ – HAH

    Your vehicle connected to the internet, your own personal stazi – are you a good driver? Do you obey speed limits, do you drive aggressively – demerits for your social score!

    1984 has arrived in full force and most are daft to the future effects of the current reams of data being collected.

    Be smart and have personal conversations away from such things because everything is spying on you these days, whether you ‘allow’ it to or not.

    • Thanks for pointing this out. So many people don’t understand that everything is monitored and recorded. We put the devices in our own homes, vehicles and pockets.

      • Should mention the nanny stuff in all the 2020 model cars as well, some call home via cell service the owner is not aware of with an installed chip. Big thread on the 4Runner boards about how to disable.

        • People have been disabling OnStar on GM vehicles for years.
          There are quite a few YouTube videos on how to do this.
          The reason is even if you don’t subscribe to OnStar,
          it will still use GPS to track you. This goes back to 1996.

    • ^^This^^

      And yet, so few are willing to give up the “convenience”. Folks agree that privacy should come first- but they happily go home to their “smart” houses, refrigerators, TV’s, beds, shower heads, toilets, mirrors…

      All of these companies/products can only get away with what we allow them to. Just. Say. No.

  7. “…and the company’s dubious record of altering data at the behest of police departments…”

    How the hell is this not perjury, false reporting, and/or other crimes of perversion of justice?

  8. Moot point. Are we still pretending that Google, Siri and Alexa can’t hear everything that’s going on? Guaranteed every Thuggy McThugface blasting cousins in Chicago has a phone in their pocket.

    Real time audio recording and location tracking is occurring. It might not be widespread (yet) or admitted but it is happening under this unholy alliance of corporate technocrats and political oligarchs feeding the military industrial complex.

  9. My Samsung 42″ flat screen in the kitchen has started spouting voice-over verbiage at turn on; channel changes; turn off. Very, very fast (usually not able to understand anything…one or two words intermittently) English speaking female voice. Not set up to be or connected to internet. Running wired from Spectrum cable box as is large TV in family room…it doesn’t do audible voice-overs..

  10. Lol

    No one cared when they were eavesdropping on Trump. No ones cares if Alexa or the echo dot eavesdrops.

    What’s the problem?

    • The civil liberties crowd did not complain when the ACLU went to court, to force the police to turn off their badge cameras. Before unarmed Trump supporters were beaten by Antifa.

  11. I don’t know why anyone is complaining? Electronic eavesdropping has become acceptable by all sides for decades now.
    Libertarians, Liberals, the Left, Conservatives, the independent folks, everyone accepts electronic eavesdropping. Until they’re Ox gets gored.

    Even the Libertarian John Stossel asks why are people so upset when multi-billion dollar private companies share your information with others???
    Since these companies are now sharing this information with the government. Which they have been sharing private communiations with the governemnt for many years now.

    Everyone has a cell phone camera.

  12. “ShotSpotter is Too Susceptible to Fraud, Abuse, and Eavesdropping”

    As they say, “That is a feature, not a defect!”

  13. “Former Water Walker”: You’re weak, so you hide behind a fake name while you call people who are,like everyone else, better than you,names. What a p***y. Why don’t you publish your real name? Why don’t you go over to a Black man and say the words you write? Because you’re a coward and you’re stupid and you’re a loser, that’s why. And since you’re a loser, you’re wasting your life popping off to a bunch of strangers who’ve never even met you and never will. Like everyone else, they don’t care anything about you, nor should they.
    Well, as someone who does have a real job, I have to get back to work. I won’t be checking back in, so don’t waste any more of your life trying to convince me you aren’t what you are. I do have a life.

    • If you were in a PUBLIC bathroom then likely.
      SCOTUS has ruled that your conversations can be overheard from a helicopter
      that is 400 feet overhead.
      That is long before personal drones which are free to observe and record you.
      Once you leave your house you have no reasonable expectation of privacy.
      This applies to ALL public places and equipment.
      People may not like it but look how many people have dash cameras.
      They make what happened in an accident very clear.
      The SCOTUS ruling has good and bad.
      It’s pretty much brown and white.
      If the cops or feds are aiming a parabolic microphone at your window in your home,
      that’s illegal. If you call you neighbor names though an open window, that’s legal.

  14. I’m glad everyone has their own personal high-tech eavesdropping device. Also known as a cell phone with camera.

    “Psycho BLM activist & his wife fight with cops at scene of deadly officer involved shooting.”
    17 min long

    • Having a personal “eavesdropping” device is perfectly logical for recording others’ actions for your personal benefit. There have been devices like this available for decades- video recorders, voice recorders, “dumb” phones, etc.

      But having a device that eavesdrops on YOU personally, outside of your control, without your knowledge or consent- that’s just… foolish.

      But, to each their own.

      • I agree with you it is foolish. However this started because people who hate the government wanted the police to have body cameras. Something that conservatives were actually against. And what has happened is it’s the cameras that have shown the police to be far more honest. Than their haters ever thought.

        And the criminals are being caught continuously with their dishonesty on video. Plus now it doesn’t matter if the police read you your rights upon arrest. Because that videotape will be played in court and it won’t matter if your rights are read to you or not.

        The ACLU that once demanded badge cams for the cops, Now goes to court to force the police to turn them off. The prison population is going up because of camera video evidence.

        • The difference between this and badge cams is that the badge cams only record (roughly) what the officer can see and hear. Nobody has an expectation of privacy in front of a uniformed officer, but people do have an expectation talking in an empty street. There’s also the issue that while badge cams are just a few tweaks to established everyday technology (digital camera) that were already omnipresent at adoption, and legal issues have largely been solved for decades (dashcam) if not centuries (the officer can almost always testify to his own senses), while gunshot detectors are entirely new technology that doesn’t even work right being used indiscriminately and has no established legal bounds or clear evidencary merit. At best they just tell officers of a possible crime’s aftermath while also recording absolutely everyone.


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