A neighborhood pitbull killed my dog

Just taking a walk and then this happens....pit ran across Lowell rd. Knocked my husband down but the camera was still on....you can hear my little Bear crying out as the pit was shaking him...the vet had to put him down because of the spine and wind pipe injuries were too severe...I reported it...Animal Control did nothing. They have to keep it on muzzle and leash when out..The dog lives at 2227 Lowell rd. Everett