Denver Mayor Mike Johnston looks to expand city's Flock camera program

Mayor Mike Johnston plans to announce an extension of Denver's Flock camera program, multiple sources tell CBS Colorado. The contract expires at the end of October and the announcement is expected soon.

While some privacy advocates are critical of the mass surveillance system, Johnston has been a strong proponent of the crime-fighting tool. 

Sources tell Investigator Brian Maass that Johnston will announce significant guardrails to prevent federal law enforcement from accessing data collected by the camera system.

There are more than 100 cameras at around 70 intersections all across Denver snapping photos of license plates as cars pass through. But, while the Denver Police Department calls it a gamechanger, some Denver city council members say the technology is an invasion of privacy and leaves too many opportunities for misuse.