More Minnesota police using body cameras, but what's the goal?

If Burnsville police pull you over on a traffic stop, a tiny camera on the officer's uniform will record the encounter. If you're cited, the cops may keep the video for three years.

Burnsville officers are required to flip on the cameras at traffic stops or other potentially volatile situations, said Chief Eric Gieseke. The video, he added, also helps officers record statements by victims and witnesses.

Less clear is whether the cameras are helping to catch criminals or protect police from lawsuits.

Burnsville, the first department in Minnesota to use the cameras regularly, doesn't have data to show cameras have cut officer complaints and incidents of use of force, although sometimes people drop complaints against officers after they've seen video of their encounters, Gieske said.

Faith in the cameras, though, is strong enough that they're becoming part of the routine for a growing number of Minnesota police officers. Duluth police added body cameras this year. Rochester and Minneapolis are in the planning stages.

Nationally, the talk over police body cameras has accelerated in recent weeks after an officer in Ferguson, Missouri, shot and killed an unarmed teenager. But before cops start recording encounters with citizens and suspects, observers say police and city officials need to first consider how and when the cameras will be used.

"I think where we have to be very careful is to think that this is the be-all, end-all," said Howard Wasserman, a law professor at Florida International University.

While the technology is very promising, body cameras haven't been in use long enough to show they directly reduce complaints against officers and uses of force by officers, he added.

Proponents of the use of body cameras say when encounters between police and the public are videotaped both parties tend to be on their best behavior. Data recently collected by the Rialto, California, police department support that claim. After Rialto officers began wearing the cameras, the department saw an 88 percent drop in complaints against officers and a 60 percent drop in the use of force by officers over a year's time.

In Burnsville, officers are not required to tell people they are being recorded but also cannot edit the footage, Gieske said. The department began using the cameras in 2010 and treats video like any other police document subject to government data practices law.

As long as the video is not part of an open investigation, it can be made public by request, Gieske said, adding that the length of time video is stored depends on the type of case.

Spring Lake Park police are currently replacing squad car cameras with wearable cameras for officers. Police Chief Doug Ebeltoft said he wants the body cameras to activate automatically when the squad car lights are turned on.

Minneapolis Mayor Betsy Hodges is proposing to spend more than $1 million next year to start equipping officers with the cameras. A pilot program involving 36 officers is planned for this fall.