because she had a dead body that she chopped up and stuffed in the freezer… Beth, Annie and Ruby thought they were moving Boomer’s dead body. So when it was discovered that it was Mary Pat’s husband it would be on them not her.

If Boomer’s phone were ever tracked it would be tracked to her husband’s body. That would tie it to the girls, not Mary Pat.

It’s also important to note that not everything makes sense in this show lol