ShotSpotter audio sensors deployed in East, West Baltimore to help BPD detect gunfire

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Baltimore Police Department spokesman T.J. Smith (left), Interim Police Commissioner Gary Tuggle (centeR) and Deputy Commissioner Andre Bonaparte demonstrate ShotSpotter. Image via Facebook.

A network of highly sensitive audio sensors were recently placed atop buildings across West Baltimore. When a gunshot rings out, they’ll pick up on the frequency and send a clip to audio analysts at the Newark, California, home base of gunfire-detection software firm ShotSpotter. If the sound checks out as actual gunfire, an officer here in Baltimore will be notified by an app on their phone.

The whole process takes somewhere between 30 seconds and one minute—far shorter than the typical response time for an officer dispatched to a scene after a 911 call.

“You’re getting instantaneous intelligence as an officer before you even respond to the area where this occurred,” explained Baltimore Police Department spokesman T.J. Smith at a press conference Friday.

Baltimore is now among more than 90 cities equipped with ShotSpotter technology. The company and police have deployed a number of the sensors in a five-square-mile area of the Western District—BPD officials said they did do know how many—and more will be added over the next month in an equal-sized area of the Eastern District. Both areas are among the smallest of Baltimore’s nine police districts, but suffer from disproportionately high gun violence, Smith noted.

Interim Police Commissioner Gary Tuggle, who was appointed to lead the department just last month after Darryl De Sousa resigned amid a federal investigation into his failure to file taxes, said the technology “will aid us significantly in the crime fight.”

The installation was funded with grant money from the Bloomberg Foundation, a gift announced by Mayor Catherine Pugh and others late last year.

ShotSpotter has been visiting Baltimore over the spring, working with police and the mayor’s office to take stock of where it would go, and reaching out to communities to familiarize them with their product—and to see if they could get any takers to install the sensors atop their private buildings, supplementing the public buildings they were already using.

Company reps held an April 19 meeting of the Western District Community Relations Council, a body of neighborhood groups and stakeholders that meets monthly at the Western District station in Sandtown-Winchester.

ShotSpotter director of public safety solutions Ron Teachman speaks at the Western District Police Station on April 19. Photo by Ethan McLeod.

Ron Teachman, a former police chief of South Bend, Indiana, who left in 2015 to work as director of public safety solutions for ShotSpotter, preached the company’s tagline: “Detect. Protect. Connect.”

Reflecting on his nearly four decades in law enforcement, he noted most officers have shared with him they rarely actually see any gunfire: “They’ll hear gunshots, but they don’t witness it. No matter how many cops you put in Baltimore, they’re not gonna witness it.”

He also said residents—”good people like you,” he told neighborhood and faith leaders—oftentimes wait minutes to call 911 when they hear gunfire outside, or don’t call at all. The reasons, he said, range from resignation about the efficacy of police to general apathy to a reliance on the idea that someone else will take the initiative.

In a walk-through of the technology, Teachman explained that with “math-based intersecting hyperbole,” or a series of calculations that determine the speed of sound ringing out after apparent gunfire, the firm’s audio analysts in California can measure the frequency and see if it was a firecracker or some other loud pop instead of a real gunshot.

If the it’s a gunshot, the company transmits the data to police—in Baltimore, that will go to Strategic Decision Support Centers in the Eastern or Western Districts—who will then reach out to officers in the area. The notification also goes right to an officer’s phone, depicting the location on a map with a radius around a dot where the sound rang out.

West Baltimore community leaders on April 19 responded warmly, applauding the presentation at the end, with some volunteering their buildings for sensors. Those in the room had already referenced several recent shootings before the presentation, and welcomed another option to help police potentially solve gun-related crimes more quickly–or at least respond to an area faster.

Even so, one could imagine the technology could spur privacy concerns. Philadelphia-based National Public affiliate WHYY-FM referenced a couple examples from Oakland in a 2016 report.

In one case, police were able to use a ShotSpotter audio clip to determine that a suspect who shot a police officer serving a warrant was aware he was attacking a cop because the microphone captured the command, “Freeze, police!” In another, prosecutors used a ShotSpotter audio file that captured a shooting victim shouting his killer’s name to help convict the shooter in court, WHYY reported.

While ShotSpotter wound up aiding law enforcement in those instances, both cases offer examples of the technology recording sound beyond solely gunshots. But ShotSpotter reps assured that’s not within the capabilities of the microphones being deployed in Baltimore.

“It’s only bangs and booms,” Jack Pontious, the company’s Northeast region director, told Baltimore Fishbowl of ShottSpotter’s frequency range. “We only listen for things above that decibel level, and that’s where we operate. Everything below there, like the conversations that we’re having right now, it doesn’t affect.”

Teachman also mentioned the American Civil Liberties Union had raised concerns about the technology in the past, but said they had been addressed. (For what it’s worth, ACLU senior policy analyst Jay Stanley wrote in a blog post in 2015 that he was worried about data storage and ShotSpotter source code, but hedged his concerns: “I am not losing sleep over this technology at this time.”)

Asked for comment, a spokeswoman for the ACLU of Maryland said the nonprofit lacks expertise on ShotSpotter’s technology and thus declined to speak about it. The national ACLU did not respond to an email requesting comment.

On Friday, Smith noted that police had already recorded multiple instances of gunfire on Thursday evening and Friday morning after deploying ShotSpotter. He showed the areas on a map: one on Eutaw Place, where he said it sounded like two different guns went off; another on Bentalou Street; yet another on N. Dukeland Street at 9:30 p.m. Thursday.

Tuggle expressed confidence in the new technology. He pointed to Chicago’s success with ShotSpotter, which he said has produced “double-digit reductions” in shootings in the city’s worst districts. “The concept works there, and we’re confident in its ability to work here.

Even so, he maintained it’s no “substitute” for 911. “If people are hearing gunshots, they need to dial 911,” he said.

The “true value” in ShotSpotter, he argued, is improving response times for emergency personnel. Asked if he thinks it will drive down gun violence, Tuggle said it would be “hard to tell” because “you can’t predict people’s intent or behavior, and you certainly can’t control it.”

However, he said, “we’ll be able to get more in front of it than behind it.”

Ethan McLeod
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