New Surveillance Program Listens For Gunshots, Get Police There in Minutes

By Veronique Greenwood | May 30, 2012 12:09 pm


These days, our artificial ears and eyes are better than ever—and more ubiquitous than ever. A business recently profiled by the New York Times seems to embody both what’s most promising about such pervasive surveillance and also what’s potentially disturbing.

ShotSpotter sells and helps run an automated gunshot-reporting system to police departments, for a cost of $40,000 to $60,000 per square mile. Recording equipment is installed in neighborhoods and linked software that records sounds that could be gunfire, analyzes them to identify which are actually shots, and then submits its findings for review by a trained employee in the company’s Mountain View office. If a human verifies that the sounds are indeed gunfire, the police are notified with the location of the shots, pinpointed to within 40-50 feet. All this can happen in well under five minutes, meaning police can be there right away.

Police officials who spoke to the New York Times were generally impressed with the system’s sensitivity, especially if they were from high-crime towns like Richmond, CA. It certainly ups the number of shots police get word of:

If nothing else, ShotSpotter has made it clear how much unreported gunfire takes place on city streets. In many high-crime urban neighborhoods, gunshots are a counterpoint to daily life, “as common as the birds chirping,” as Cmdr. Mikail Ali of the San Francisco Police Department put it. But whether out of apathy, fear or uncertainty, people call the police in only a fraction of cases. In the Bayview-Hunter’s Point neighborhood of San Francisco, for example, where one square mile is covered by ShotSpotter sensors, only 10 percent of the verified incidents of gunfire detected by the system were accompanied by 911 calls, Commander Ali said. In Oakland, Sergeant Bolton said, only 22 percent of the verified gunfire the system detected over a three-month period was also reported by residents.

But the cost of the system, and the question of whether it records things it shouldn’t, are causing some controversy.

ShotSpotter has, in at least one case, recorded voices along with gunfire (though it only starts recording once a shot has been fired, or at least once a shot-like sound is heard, according to a vice president of the company). Two men who are accused of murdering another in New Bedford, Massachusetts, last year can be heard on the ShotSpotter recording of the events. Whether what they say on the recording can be used as evidence in the case has yet to be decided. It hinges on whether you have a reasonable expectation of privacy after you’ve fired a gun in a public place.

Image courtesy of Robert Nelson / flickr

  • Iain

    I think that once you start shooting all expectations of privacy should be gone, thus allowing the recordings as evidence. unless one uses a silencer which would imply a desire for privacy.

  • JDoors

    So if a drone flying overhead randomly SEES you shoot at someone, that’s (presumably) admissible evidence, but an audio-only recording after the initial act is questionable?

  • deirdrebeth

    I stopped reporting gunfire after I called the police in Buffalo, NY on one. My BF at the time was an EMT so we had a scanner. We heard the officers report back that there was nothing going on at the same time as we heard more shots being fired. Either they were deaf, or they weren’t where they said they were. The next day I found a bullet hole in my car, reported it again and was told “oh that must be old”. Yeah. They pretty much had a “if you’re not actually seeing a crime don’t bother us” attitude.

    I’m guessing I’m not the only person who’s stopped taking the time.

  • Zack

    @JDoors: U.S. law generally allows unlimited public video surveillance but places strict limits on interception of audio. While your actions in public are presumed to be public, there is still a reasonable expectation of privacy. Thus, even actions you intend to conceal may be recorded and used as evidence, whereas if you make an effort to keep a conversation private, the law examines whether you have a “reasonable expectation of privacy.” So video drones: ok. Audio drones: not so much.

  • Ken

    I probably read too many DC Comics, but my first thought was that crooks could use the technology to decoy the police away from where the real crime was being committed.

  • Bill

    They’re hardly new – Redwood City (a few towns up from the company’s office) had one a decade or so ago, and later took it out.

    And the voice privacy problems aren’t just for the people talking near an active shooting – they potentially include anybody talking any time close enough for any of the mikes to pick up their voices. (That’s probably not everywhere in the city, since gunshots carry farther than voices, and they probably don’t store all the sounds the mikes pick up. But they could, pretty easily.)

  • James

    James from ShotSpotter here: Bill, Redwood City never removed its ShotSpotter system. We’re still installed there, 15 years later, and we are still under a maintenance contract.

  • floodmouse

    Do fireworks register as gunshots? Fireworks are very popular in my neighborhood. I can imagine some unpleasant scenarios where kids setting off fireworks get confronted by an armed response by police officers. I can also imagine that after responding to fireworks several times, conscientious officers might feel this was a case of “crying wolf” and fail to respond to a real gunshot.

    It’s even more easy for me to imagine that unconscientious officers would prefer not to respond in the first place. I’ve reported a couple things to the police (not gunshots), and their attitude was basically that without videotape or a witness, they weren’t going to be bothered with taking any action or filing a report. The first officer was merely patronizing, and the second was insulting.

    The problem with the audio surveillance is that voices picked up on the recording might not belong to a person who fired a gun. What if someone setting off fireworks talks about some marijuana they want to buy or sell? Is that evidence admissible? What if someone fired a registered gun for target practice in their back yard, and the next door neighbor happened to be chatting about how he owes a lot of child support, but the court can’t garnish his wages because they don’t know where he lives? Is that evidence admissible too? Selling marijuana and not being able to afford to make child support payments may be against the law, but they are not transgressions on the same level of magnitude as shooting someone. Even if the recordings are found to be legally inadmissible, how could you prevent police officers or court officers from acting on the knowledge they got from the illegal recording? For example, they could set up a surveillance of the kids wanting to sell or buy marijuana so they could arrest them at another time. The officers might regard them as “fair game” since they are breaking the law, but other people would be breaking laws at the same time and the particular individuals inadvertently captured on the audio recording would be prejudicially targeted.

  • Doina

    Yah, this is the next step, like it or not. The end of freedom fox

  • James

    I’ve heard anecdotally of this type of system being in place in Chicago for quite a while now. If true, what is ‘new’ about the particular program mentioned in this article?

  • Kaviani

    The NRA is going to be all over this. I won’t expect it to stick. Besides, it’s a law enforcement priority to serve and protect LOW crime neighborhoods first, then worry about the riffraff. 911 is still a joke.

  • Jim

    I have heard of these being around for a long time in Chicago. I can’t tell specifically from the article what is new about this. I have heard that fireworks do in fact trigger the system in Chicago and the police can get a relatively accurate location as to where the gunshot (and/or fireworks) occurred.

  • http://n.a. Dave

    We should routinely surveille the ubiquitous dirty politicians in Washington and report them to the people of America.


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