With all of the cadaver dogs alerting at a shallow grave in their search for Susan Powell and the arepolice not finding any human remains in the grave, they need to do the following things.
1). Dig deeper. We had one suspect dig a 7 foot deep grave near Amboy Washington
and dump the victim there.
2). Bring in Ground penetrating radar to see if there's anything deeper.
3). Draw a circle 1 mile around the grave site and bring in the cadaver dogs to work an loose air scent grid in that area. If a cougar or coyote spread the remains. That's where they will find the bones.
4). Or a suspect removed the remains and the dogs are alerting on the body fluids that soaked into the ground. Do a DNA on the soil and see if it matches the DNA of Susan powell.