The fresh grave won't work. Think!
at least up here, most graves are 'cleaned' after about 10 years, in which case they will notice the bodycount doesn't match. With DNA and all that stuff, chances are the will know who it is and the body is found. Not saying you'll get caught, but the body will be found and that was the question
If you want the body to not be found, you really have to make it vanish, not hide.