Sometimes dogs get out. It happens.
Based on your statement I can only assume that you dont have a dog.
Thorne,
I am sorry you had to go thru this, I hope that the people were polite to you, and you, to them, and maybe they will give you an update as to his health.
One of my next door neighbors hit my childhood dog and killed her. It was awful, and he felt bad. He had liked our dog so much, that he bought the same breed, about a year before this happened. (she was an aus shep)
Sometimes these things happen, just be glad you did not kill him.