In an instant, the sensors from East Palo Alto's ShotSpotter can pinpoint the exact location where these gunshots were fired.
"Then the detectives would know that this may be an area to start looking for casings," said East Palo Alto Police Chief Ron Davis.
Davis says last year, ShotSpotter detected 1,300 incidents in East Palo Alto -- a town just three-square miles in size and once dubbed the "murder capital of the United States".
"So around here, and around here are some of the highest concentrations of activity," said Davis.
But when the city's police chief began noticing these clusters of reoccurring gunshots, he wanted to know how it was affecting the people who lived there.
"UC Berkeley did a survey that showed many of the residents were afraid to come out because of the gunshots, so they were not engaging in the healthy activities that many of us enjoy that live in neighborhoods that are not affected by gun violence," said Davis.
Davis says the areas dotted with gunfire were plagued with high rates of chronic disease and child obesity. So instead of beefing up enforcement and arrests, he turned two gang-infested parks into "fit zones".
It's a rare sight to see, but twice a week police officers conduct Zumba sessions at Jack Farrell Park. They play volleyball with the residents. They organize power walks around the park and they know the kids by name.
"This is a good friend of mine, Lalo," said East Palo Alto Police Ofc. Clay Warford.
The highlight is a four-mile bicycle ride along the shoreline trails.
A health navigator also talks to parents about nutrition.
"Look how much sugar is in these. So look for a healthier choice," said one health educator.
The squad cars are kept out of sight and replaced by Segways and bikes.
"When we're in the car there's like a barrier there. You know the window might be down, but they see a black and white, they see a police officer and that's all they see. When I'm on this and when we're on the bikes, there's a lot of 'Hey, what's up? What are you guys doing? What are you guys doing out here?' You know they want to talk to us," said East Palo Alto Police Sgt. David Carson.
"You know what? That's the best thing because I wanted my kids to feel like they're secure and the policeman is a friend for them," said East Palo Alto resident Edith Rivas.
It's an unconventional approach where violence is viewed as a health problem that can be solved with a public health model. Now Rivas says her son is losing weight and the people have regained the park.
"Before I would just stay inside and play video games and watch TV," said East Palo Alto resident Brandon Alvarado.
UC Berkeley law school researcher, Sarah Lawrence, is conducting the science behind this pilot program.
"In the city overall, the shootings are down 31 percent, but in the two hotspots, it's a decline of 60 percent and 40 percent," said Lawrence.
It's only been five months in a one-year study, but if combining a crime-fighting tool with a public health strategy proves effective, Davis says the program would have reduced the crime in this park without one officer making an arrest.