The footage shows an officer telling a perpetrator to "Stop now!" He yells, "You bring your hand up, you're gonna get crushed, dude. Put your friggin' hand down!"
The chase ends with an arrest. The video came not from an observer, but from the Cincinnati police officer himself. The officer discovers his perp his carrying two pistols.
In another cop video captured one week later, the officer tells a suspect to put his hands behind his back. The response: "Tase me, then." And the officers ultimately do.
In Cincinnati, 10 patrol officers, like Melissa Cummins, are wired for pictures and sound.
"It's a head camera that captures everything that I see by the movement of my head," Cummins said.
Cummins was the first Cincinnati cop to volunteer for the pilot program - making police video portable.
"It's going to help us as law enforcement officers through this country to be able to capture that actual moment - what we're seeing," she said.
What she sees includes mundane interactions like a traffic stop (the driver says that a rock chipped his windshield) to the potentially dangerous, like a "gun run."
"It means someone has made a call into 9-1-1 stating someone is carrying a gun - is threatening someone," Cummins said.
When Cummins entered the housing complex in question, her camera was rolling and her gun was drawn.
"Open the door! Let us see your hands!" she yells.
The alleged gun carrier apparently had gone inside. No arrest this time.
But if there had been, "Instead of a jury or a judge taking my word, now you can hear it," Cummins said.
Cincinnati Police Chief Tom Streicher calls the tiny camera a powerful tool for bringing evidence to criminal court.
"It is the real thing. It is the evidence. It is the incident as it's unfolding," Streicher said.
The cop camera captured when a different Cincinnati officer chasing a drunk who had allegedly disrupted a convenience store - the chase all recorded from the officer's point of view and another arrest.
"You've got very solid evidence here that's preserved for as long as we need it to be," Streicher said of the video.
Cincinnati believes the video will not only help convict people, but help cops defend themselves from allegations of rudeness or even brutality.
"What better way of evaluating that officer's conduct by taking a look at what that officer is seeing?" Streicher said.
That's what happened in Fort Smith, Ark., where cop camera video exonerated an officer who used lethal force last November.
The officer orders a man to "Drop the gun!" When the man refused nine times to put his pistol down, the officer shot him.
The cameras are made by the Arizona-based Taser company, the same one that makes Taser guns now used by 15,000 U.S. law enforcement agencies. Cops feed the video - encrytped - to Taser, which then makes clips accessible to police through a password-protected website.
"There clearly is a very solid chain of custody with that evidence - and that's tremendous," Streicher said. "It cannot be altered by anybody inside this organization."
But skeptics worry a police officer's word may be trusted only when there is video to support it and the presence of a camera recording every citizen interaction could make some witnesses reluctant to speak to cops.
Still, Streicher hopes to get federal grant money to equip all 800 patrol officers in Cincinnatti with cameras. They cost $1,700 each, plus $100 a month to service.
"i think that every uniformed officer working, that's out on the street, should be wearing this," Streicher said.
In addition to Cincinnati and Fort Smith, the tiny cop cameras are being tested in San Diego and San Jose, Calif. and Aberdeen, S.D., which has already committed to buying 20 of the cameras.