If I had to dispose of a dog, I'd make sure to lure it away during broad daylight, doing so at night might make foul play suspect.
Once I had it lured away, I'd kill it quickly and painlessly. Bag it up, throw it in the truck and drive up to the mountains.
Dig a grave, fill it quarter ways with lime and other corrosives and proceed to de-bag the dog. Throw the dog into the pit of corrosiveness and pour some more lime on him then proceed to cover the hole up.
Then I'd burn the bloody package I bagged him in and proceed to drive home.
