The Denver Police Department is testing several officer-worn video cameras as it strives to remain one of the nation's "most innovative" police agencies, a spokesman said Monday.Police officials will demonstrate various models the department is trying at a Tuesday afternoon news briefing.The so-called Body-Worn Digital Recording Devices are "essentially portable camera systems that record officer interaction with civilians," Denver police spokesman Lt. Matt Murray said in a news release Monday.One firm, COBAN Technologies, makes a wireless pager-sized video unit that is worn on an officer's chest. Denver police have not named the manufacturers of officer-cams they're testing.Other police agencies say the cop-cam is a new 'crime-fighting tool' that helps gather evidence, protect officers from false police brutality accusations and improves community relations, according to a 2010 article in TechBeat, a National Institute of Justice publication.Some agencies say they adopted the officer-worn cameras because, at a price range of $70 to $900, they are cheaper than $5,000 patrol car dash-mounted cameras, which only capture what the patrol car is pointed at. "The difference is the body-worn cameras can go wherever the patrol officer goes when he steps away from the patrol car, such as into an apartment building or a house, and record what the officer sees and hears," the TechBeat article said. "Detectives can use the cameras for field interviews and victim interviews."The Lafayette (Colo.) Police Department switched from patrol car dash cameras to inexpensive officer-worn cameras in 2009.Reasons to use officer-worn cameras are to increase officer safety, reduce agency liability, reduce officer complaints and improve the public perception of police," Lafayette police Sgt. John Sellers told TechBeat.