JACKSONVILLE, Fla. – Jacksonville is getting new technology to battle gun violence in some of the city's most crime-plagued neighborhoods. It's called ShotSpotter, which is gunshot detection software -- similar to that used to detect earthquakes.

The I-TEAM discovered there were 765 non-domestic shooting in Jacksonville in 2016 alone. The company that makes ShotSpotter says nationwide, its technology is part of a 12-percent reduction in gun violence in 2015.

Gun violence is something the family of Amber Bass knows all too well. Four years ago, the 22-year-old was robbed and shot in front of her home on Jacksonville's Westside.

"The neighbors had said that they heard a gunshot but they did not call right away," said Amber's sister Robin Lezcano.

Lezcano says she heard some sort of noise herself, and she did report it to police, but she didn't go outside right away. When she did, 15 minutes later, she found Amber in the driveway -- and it was too late. Amber couldn't be revived and her killer had vanished into the darkness.

"It's just like this weight on your chest and you know, every day, you hope you get a phone call or something. Some kind of lead," said Lezcano.

But nearly four years later, that hasn't happened. Amber's robbery and murder remains unsolved.

"I feel like if police had been there sooner, they may have caught the car driving away, they may have caught someone throwing a gun outside," Lezcano told the I-TEAM.

Next month, The Jacksonville Sheriff's Office will have ShotSpotter installed as a new tool that JSO says will help police officers get to shootings quicker.

The company, SST, will install hidden microphone sensors around high-crime areas. If there's a gunshot, the software uses triangulation to pinpoint where the gunfire came from. That data goes to the company's dispatch center and is sent out to nearby officers.

The I-TEAM went to Denver to see ShotSpotter in action. The Denver Police Department has been using it for the last two years to cover 11 square miles.

"More often than not, they are within 5 to 10 feet of where the gunshots were actually occurring from," said Denver Police Lt.  Aaron Sanchez. "On average, we probably get about 10 alerts per day."

Sanchez is in charge and he showed us shootings that had occurred in the Denver area over the last 12 hours. He says police get a notification on their cell phones telling them where the gunfire is - even letting them listen to the shots.

"It's about 45 seconds by the time it's hitting the cops' computers and telephones," he added.

That means police are able to get there sometimes within a minute or two.

"I think the biggest success for us is the ability to investigate, to get to victims quicker, to have the opportunity to arrest suspects," explained Sanchez. "It seems to be worth the money, yes."

While ShotSpotter doesn't catch indoor shootings, Sanchez says it's surprisingly accurate for those that happen outside.

"More often than not, they are within 5 to 10 feet of where the gunshots were actually occurring from," he said.

The software was developed because of a national problem. Police say many people just don't report hearing gun shots. On average, studies show less than 20 percent of gunshots are actually called in, so more than 80 percent are unreported. 

In crime-ridden neighborhoods, people may become desensitized or they might not know where the shots are coming from. But in 2016, ShotSpotter systems installed across the United States detected 74.916 incidents. And, they're especially prevalent between 1 a.m. and 3 a.m. -- when most people are sleeping.

"We can also view that in real time and be able to respond a lot quicker to those areas," said Jacksonville Sheriff Mike Williams.

The sheriff says he's looking forward to a pilot program in Northwest Jacksonville, the area hardest hit but gunfire.

Starting in June, Sensors will cover a 5 square mile radius. City leaders agreed to pay for it: $435,000 the first year, and $325,000 for each following year.

LaWanda Taylor is in favor of the technology. She says if it was in place three years ago, someone may have been able to save her 17-year-old son, Errin Brooks.

"My son was shot at 8:30 that night and he lay there until 6 something in the morning," said Taylor.

Not one person called 911.

And Amber Bass' sister, Robin Lezcano, she tells us she can't help but wonder how ShotSpotter may have made a difference in Amber's case.

"I feel like, yes, it could have made a huge difference. If the response time is within seconds, those are seconds and minutes you just can't get back," she said.

Even after ShotSpotter is installed, police are still going to rely on witnesses, and they absolutely want people to report any gunshots. But they say the system is another tool they can use.

As we reported in April, the Jacksonville Sheriff's Office is also getting a bullet identification system called NIBIN. That technology will allow police to enter shell casings into a database to look for links to other crimes.

WATCH: NIBIN: JSO getting bullet-linking technology

Sheriff Williams says ShotSpotter will hopefully lead officers straight to the shell casings, giving them evidence that could crack the case.

Overall, the more than 70 agencies with this secret surveillance seem pleased with the results. (See agencies in interactive map below.)

However, ShotSpotter has had its criticism. For example, police in Charlotte, North Carolina recently stopped using the technology after leaders said it wasn't effective in cutting down on crime -- especially for the price. 

Police in Miami had the same complaint a few years back, but recently announced it is installing an upgraded version of the system there.

Other Florida cities with ShotSpotter include Riviera Beach and Tampa.