Police said an officer shot and killed a Rottweiler after he was attacked while trying to help a man possibly having a seizure.

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The Pittsburgh Bureau of Police said just before 12:30 a.m. Sunday, an officer responded to a report of man having a medical issue on the sidewalk.

Police said when the officer arrived, the dog was running loose, charged the officer and bit him in the back of the thigh, knocking the officer to the ground. As the officer was getting back up, police said, the dog lunged again.

That's when police said the officer fired his gun, killing the dog. The officer was then able to provide first aid to the man on the sidewalk.

During the investigation, police said it was determined the dog belonged to the man possibly having a seizure.