7yo little boy was attacked by a dog while riding his bike outside. Should the parents have kept a better watch or should the owners of the dog keep better control?

A little boy was recently attacked by a dog in my town. He was riding his bike outside his home. There was a chained dog across the street. The story is unclear on whether or not the dog got off its leash or the little boy got too close. The dog attacked the little boy ripping his face into pieces. After facial reconstructive surgery, there are now four rows of stiches stretching across his face. He will fully recover but he will not have the same facial features and he will forever have a scarred face. The fate of the dog has not yet been decided. 
There are more than some people that believe this animal is at no fault. On social media, most of the blame is on the boys parents for not keeping a closer eye on their child and very little on the pet owners for keeping an aggressive animal. Should the blame be on the parents of the young boy for not teaching or watching their child closer? Or should the blame be on the pet owners for keeping an aggressive animal and not taking proper precautions to ensure the children have a safe environment to play in? 
Personally, I believe the owners of this animal should be criminally charged for exposing this dog to the public and I believe this dog should have been put down immediately. The parents of every child could do everything right and this dog, now or later, would eventually hurt a child. If this matter is left alone, the dog WILL attack again. The little boy was seven, he is growing and learning. He, nor his parents, should have to worry about an aggressive animal attacking him in his home neighborhood. We cannot control the horrors of this world or the endeavors of our neighbors but that does not mean it is okay to contribute to it. He should not fear walking outside or riding his bike ANYWHERE. If these pet owners want to keep their overly aggressive animal, they need to take overly protective measures to protect the people surrounding them. 

Vote below to see results!