[T]he proliferation of private surveillance cameras around the city and the nation -- and their public-sector counterparts -- have spurred debates about privacy. But more quietly, in ways large and small, the cameras are doing something else: they are transforming police work, joining witnesses and fingerprints as key tools in investigations.
"One of the things we do at the scene of any crime is look for cameras, private-sector cameras," said Raymond W. Kelly, the New York City police commissioner. "It was not standard procedure 10 or 15 years ago. . . ."
[C]ameras now play a role in recording evidence on crimes from pickpocketing to murders to bombings. Two week ago, when two handmade grenades exploded outside a Third Avenue office building, detectives immediately began a search of surrounding cameras. They came up with more than 40 video recordings from more than 20 locations, including one from directly across the street that showed the explosions. Using the video, the police have been able to identify several potential witnesses.
"It used to be you got to a crime scene and what you had was whatever was left there: a cigarette stub or a tire skid," said John Firman, director of research for the International Association for Chiefs of Police. "Now it's possible to have between 5 to 10 video clips that they can gather from that area, depending on how public that area is."