Unlikely Kaiser. When there is an unsolved crime, and a significant amount of time has passed, we begin manufacturing improbable scenarios to desperately reach for anything that even remotely resembles a possibility. In reality, crime types tend to follow pretty predictable patterns that LE are expert at tracking. (If/then scenarios). The suspect profile is predictable as well. Then why aren't all crimes solved, and swiftly? First, resources. Second, time decay. Third, geographic scope of the search.
Let me give you an example of the predictability of crimes. If you are female, where do you hide valuables?
Answer: If you are like 98% of women, you hide valuables in your underwear drawer, and that is the FIRST place a burglar goes...
Anyway, you get my point. The phone scenario you describe is out of scope.
LE is methodically conducting this investigation, and they WILL solve this...and soon. Keep praying for Sierra!