Whether surveillance cameras actually help deter crime is a matter of debate, says the Associated Press. In Baltimore, police began using the cameras in 2005. There are now 300 throughout the city, and police say violent crime has dropped by 15 percent in the places where the cameras are installed. Prosecutors aren't impressed. “We have not found that they affect the conviction rate at all,” said Margaret Burns of the Baltimore State's Attorney's office.
In 2006, the cameras led to nearly 2,000 arrests in Baltimore. About a fourth of those arrests – 407 – led to guilty verdicts, while 386 resulted in charges being dropped because of insufficient evidence. Another 599 people were swiftly released because the quality of evidence – mostly surveillance camera tapes – was too poor to even file charges. “It's infrequent that we can actually associate the footage with the defendant,” Burns said. “You basically see a lot of people in sweatshirts and jeans and T-shirts. You don't have any identifying characteristics you can use in court.”When it comes to measuring crime, perhaps the most telling statistic is the homicide rate. By that measure, Burns said, Baltimore has problems the cameras haven't solved.