We’re a little south of you. However, the most favorite dog of our neighborhood (a Shih Tzu mix named “Batman”) was attacked and killed recently by an off leash pit bull. This occurred on Kansas at Taylor St NW. The owner of the pitbull allowed it to happen and then after Batman was dead, the two just walked away as if it were the most normal occurrence in their day.
The only recourse that you have is to call animal control. Good luck. And so sorry about your dog!