Ralph A. Clark remembers the first time he went for a ride-along with police. He was in Baltimore, and a teenager had been killed. He says what shocked him was not the sight of the body on the street, but the lack of reaction from people at the scene—“as if nothing had happened.”

“That is the cost of gun violence,” Clark, who is the president and CEO of ShotSpotter, a company whose technology uses sensors to identify the sound of a gun being fired, said Friday at the Spotlight Health Festival, which is cohosted by The Aspen Institute and The Atlantic.

Clark noted that although much of the focus on gun violence in the U.S. is on mass shootings, they account for about 1 percent of all shooting deaths. The overwhelming majority of gun crimes are committed with illegally obtained firearms. Not only that: very few individuals are responsible for most of those gun crimes, he said. But the vast majority of persistent, ongoing gun violence goes unreported by residents who live in communities that are often poor and under-served by police.

“Eighty to 90 percent of the time a gun is fired, there’s no call to 911,” Clark said, “which means there’s no police response, which means that gun violence becomes normalized in these communities.”