I am not sure. If in fact his phone stopped communicating on Sunday night, would that be proof that Dylan was "disappeared" Sunday night? I mean, enough to charge MR? Couldn't it also theoretically mean that his phone ceased working for good?(coincidental as that would be, in my view).
Now if that last text did not come from the house, that would be another issue, and should be enough to charge him, I would think, since he claimed they never left the house once they got there shortly after 8pm. That would make the whole evening a lie.
But I am not sure how specific the locale can be determined in such a rural area.
You're correct when you stated (his phone ceased working.)
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Any of the above could be why Dylan's cell phone stopped communicating <modsnip> November 18 2012, and has never communicated with any cell tower since.
Dylan was an avid texter, and all the sudden Dylan stopped texting Sunday night November 18 2012.