I love how the "Driving in tandem with Someone" theory has magically morphed over the years, yet no evidence has come to light in recent years that should be cause for the sudden change.
The original driving in tandem theory was used to explain that someone with not so good intentions lured maura away from civilization to do personal harm to her.
Under that scenario, however, maura would've had no expectation that she would not be returning to amherst or to her normal life and therefore, she likely would've left a communication trail with this person in some fashion (like on her computer).
Now a days, this driving in tandem partner" is someone who is helping maura escape her woeful life that includes the ever devastating $70 credit card fraud incident.
(Sarcasm alert) Wow, who wouldn't run away from life after such a dispicable crime. A crime so nasty that she was photographed in her own dorm and released within minutes and "the crime of the century" wasn't even going to be on maura's record in a couple of months.
Does anyone really believe that a minor incident involving credit card misuse, was so troubling to maura (yet she hid it and acted normal all winter break while home visiting her boyfriend and family) was cause for her several months later to flee life for good and start a whole new life in another country over it.
That theory does make for a good book though.