Karen Sutherland, the dog's owner, told reporters that Merrick suffers from dementia, and had slipped through a gate in her backyard during a storm.
"I'm a little bit in shock ... I didn't watch the video until [Wednesday] morning. It was enough to make me a lot more upset than I was last night," Sutherland told CityNews.
Christine Soti, a Collingwood resident who witnessed the incident, told the Globe and Mail that Merrick was still moving after being hit by the car a third time. "The eyes were opening and closing."
In the wake of Merrick's killing, police are facing tough questions about how officers deal with animal situations.
The Ontario Provincial Police did not immediately return a call to The Dodo, but Inspector John Trude told Postmedia Network that there had been complaints from two residents about a coyote on the loose.
"When the officer got there, it was growling," he said. "The actions of the dog caused the officer to believe it was still aggressive.