Brian: You killed a dog and burned down a liquor store just to prove a point!?
Stewie: Don't worry, he was a stray.
There is an alternate scene at the part where Brian releases the dog from his leash at the ice cream shop which can be seen in the Family Guy, Volume Eight. In it, after Brain releases the dog, it just walks away. Then a man and his son, who turn out to the dog's owners, come out of the ice cream shop and notice the dog is gone. The man then starts yelling at his son, thinking that he didn't tie the leash to the pole tight enough, and the son apologizes in Stewie's voice. Brian notices this, and Stewie tells him that that is one of his "side voices." Which could be a reference to the many characters that Seth MacFarlane voices on the show.