Be wary of it for sure. While I don't have experience with many coyotes wolves are very prominent in my area and I have definitely seen some messed up dogs (e.g. stray from the pack, in town during the day, not afraid of humans or cars) and typically the mange wolves are very skinny.

So the fact that it has a big body makes one wonder. Perhaps a shy stray dog? Small dog bread with a huskie maybe? Like I said we don't have yotes here so I don't know what it would take to make a dog look like a coyote.

Call the local vet or game warden and have them shoot it with a tranquilizer. You'd feel horrible if you shot someones pet; not a chance worth taking