Could a person have some kind of weird ...(shudder!)...implant?
Prisoners hide all sorts of things "you know where". Maybe he carries something with him everywhere he goes.
The way things are going, I think it would be odd if we don't end up hearing about more sex crimes SA is responsible for. Maybe it has been easy to get away with those type of crimes in the area he lives in due , (IMO), to the apparent lack of a well-trained, professionally run police department. The prevelance of the drug culture could also have an negative impact on crimes being reported. I would imagine that some people around there would be afraid that their report of a crime might not be taken seriously, considering the attitude shown by police on the 911 tapes.