Billy G. Cates, 18, was fined $325 last Tuesday for letting loose his dog "with the intent to annoy, worry, maim, injure or kill the squirrel," according to the Council Bluffs Daily Nonpareil and the Omaha World-Herald.
The black-colored squirrel (search) is Council Bluffs' unofficial mascot, and an ordinance protecting it has been on the books for decades.
They're not the only ones with black squirrels - for more, check here. For white squirrels, go to Olney, IL, or several others.
Incidentally, Cosmo is columnist Jonah Goldberg's dog, well known for his dealings with squirrels.