Christine Estes/KJZZ

Phoenix chose to expand its body-worn camera program to 2,000 police officers, up from 300 in the current program.

Since 2011, Phoenix police officers in the Maryvale precinct have worn body cameras, among the first adopters when Taser first introduced the body-worn cameras.

The technology was expensive then, which is why spokesman Tommy Thompson said they bought a limited number for the West Valley precinct to test.

This week, the department begins a new 30-day trial with higher quality Axon cameras.

"One of the problems with the cameras that they had up through last week, is the inability to film in low-light conditions," Thompson pointed out. "And, quite frankly two-thirds of our officers work on shifts where they're out when it's dark."

Ultimately, he said, the department will employ 1,600 cameras for the entire force to record their activity while interacting with the community.

Thompson said the equipment costs nearly $6 million and another $10 million to provide staff to review video, maintain the equipment, and process public records requests.