Acoustic sensors, new technology installed September 1 by the Chicago Police Department, can send officers to the exact spot where a gunshot was fired.
"Officers in the field are directed very quickly to these locations, resulting in arrests even before 9-1-1 calls are received in public," McCarthy said. "It happens in real time."
McCarthy said the technology is especially useful when residents refuse to report gunshots.
So far in Chicago, the sensors have been installed in two locations in portions of four high-crime police districts. The sensors can detect gunshots up to a half-mile away.
McCarthy says the technology has already led to the arrest of two felons and the recovery of two weapons.
But there is nothing cheap about this new technology. The superintendent says it costs $100,000 for every 1.5 square miles. But, he says, if it works, it's going to be a whole lot less expensive than the cost of one murder to society.
"Each murder that a city suffers, at the low end of the spectrum, costs about $5 million," McCarthy said.
Some former gang members who now work the streets for Ceasefire are skeptical, considering the city has rolled out technology that hasn't worked before, including gunshot sensors.
"You can put that in the community all you want, but by the time they get there, the person's already shot or already dead," said Ceasefire's Patrick Vance.
Although, Vance and his friends say they support the technology, if it works better than what they call failed blue light cameras.
"Honesty, if it proves to work, then why not spend money on it," said Ceasefire's Brandon Jackson.
If the new sensors prove to be successful, McCarthy says he will look for alternative funding to pay for it.