Hartford police said the teen was bit by the dog in the calf on Sargent Street. They said the dog then fled.
"This dog was just (running) around terrorizing the neighborhood," said India McDonald.
An officer spotted the dog, which police said then charged at a child.
"Dog (that are) vicious like that, they need to be on a leash," McDonald said.
The officer fired his weapon at the dog, but missed, police said. Animal control officers then captured the dog, which was taken to a veterinarian for evaluation.
"If it wasn't for the cop, everybody else would have gotten attacked," said Hartford resident Marsha Harrison.
While pleased that officers caught the dog, Harrison said it's a recurring problem. On Wednesday, Harrison said she had a rottweiler chase her in her own back yard, and two weeks ago she said the pit bull that was the subject of Wednesday's incident went after her preschool-age daughter in her driveway until a relative chased the dog away, shooting it with a slingshot.
"Even when he hit the dog, twice, it was still trying to attack the baby," Harrison said.
Police still have the dog to make sure it is current with vaccines and doesn't have rabies.
At this point, police said they have not determined if, or when the dog will be returned to its owner and if they will face charges.