I'm certain that the US government is able to easily track someone traveling on their own legitimate passport. So that kind of ruse makes no sense.
It's sort of a shame he didn't travel to the EU, as I suspect he'd get better support from most countries and would be able to travel in the EU without a passport.
He worked as a "technical assistant" for the CIA. He probably picked up a few tricks during his tenure but he didn't go through the clandestine service trainee program, which are the people you're thinking of when you think of spooky CIA types.
It's sort of a shame he didn't travel to the EU, as I suspect he'd get better support from most countries and would be able to travel in the EU without a passport.