They put a “tracker” in her USB stick.
But surely the battery in there would have been so tiny that it would only have lasted a day or two at the most.
(And I think you would also struggle to get a sensible length antenna in there as well).
And that’s assuming it doesn’t have GPS, which would make it completely impractical.
But without GPS you would have to rely on IP geolocation unless you could persuade all the telcos in the countries she visited to hand over base station information, more-or-less in real time.
So I find it quite hard to believe.
Not helped by the terrible over-acting and implausible plot lines.