So sorry to read about your pooch. We have coyotes in our neighbourhood and they scare the bejeezus out of me. (I have a mini-dachshund). From a distance, they look like dogs and then when you get a bit closer you see that isn't the case.

We've had other unwanted wildlife in our backyard and as they are protected, we were told they can't be killed but the suggestion we were given seems to have worked. We were told to put some open cups of bleach around the perimeter of the yard. I found that chlorine tablets (the kind you use in swimming pools) in an old cottage cheese container work great.

One at the gate between front and back yards, one on back fence near garbage bins and one at opposite end of back fence.

They're good because they won't spill like laundry bleach and last a long time. Evidently, it's the smell they don't like. My dog doesn't even notice them. Granted he's too short to reach or even see them.

Of course, keeping your garbage neat and tidy is very important.
Good luck!