On an early June night in 2007, Roberto Duran, 14, was walking with friends in Chicago’s Little Village neighborhood when a case of mistaken identity cut his life short.

A car – a Chevrolet Celebrity, police later confirmed — pulled up to the group and stopped abruptly. Out of it stepped a young man, who extended a handgun and shot Duran once. Then the car took off.

A witness, sitting in his own car, immediately gave chase. He kept with it for several blocks, striking its bumper with his, before finally forcing it to crash. The two men inside fled the scene on foot. For now, the suspects remained at large, and worse, unidentified.

But a nearby surveillance camera was watching. The camera, operated by the Chicago Public Schools, captured their escape. With that footage and other evidence, police were able to identify the men and charge them with Duran’s murder. It was the first use of video surveillance to track down a suspected killer, just four years after the city initiated its crime camera program.

Today, crime cameras are more prevalent than ever, and law-enforcement officials praise public surveillance systems as a crime-fighting tool. “There’s such value in video evidence,” said Mike Fergus, project manager of the technology center for the International Association of Chiefs of Police. “And it’s everywhere.”

But the swift adoption of crime cameras nationwide has been accompanied by ongoing concerns over their potential to violate personal privacy. Enticed by government grants after the Sept. 11, 2001, terrorist attacks, some police departments rushed to set up camera systems, said Sharon Bradford Franklin, senior counsel for The Constitution Project, which published a 2006 report on cameras and privacy.

“Many communities began installing systems without first developing any privacy policies or rules for the use of these systems,” she said. “The law is trying to catch up with technology.”