At the beginning of Rogue One, Jyn is imprisoned at the Wobani Labor Camp, but the Empire thinks she is one Liana Hallik. How does the Rebel Alliance find out Jyn hides under this alias? How does the Rebellion find Jyn's location?
1 Answer
The Rogue One: Rebel Dossier factbook indicates that the Rebellion proper (under Mon Mothma) have a source of information, presumably Tivik, inside Saw Gerrera's rebel cell. This infiltrator has evidently fed them information about the cell's members, identities and aliases.
Our analysis also turned up information about Jyn Erso, Galen Erso’s daughter and a former fighter for Saw Gerrera (see related file). We agreed that Jyn Erso was an essential source: she could identify Galen Erso and might know more about his research.
As to how they located her, the Rebellion apparently had operatives tasked with searching public (and semi-public) databases for her known aliases. Her name popped up in an arrest report.
We aren’t sure how Jyn Erso wound up in Gerrera’s militia, when she left, or why she did so. After that we have her Imperial arrest records as a street fighter, smuggler, and petty criminal. She drifted from planet to planet, acquiring and discarding fake names, until she was arrested on Corulag and sentenced to a labor camp on Wobani.
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We located arrest records for Jyn Erso and discovered that she was being held in a labor camp on Wobani under the alias Liana Hallik.
You may want to note that their (in-universe) dossier also contains a considerable number of other aliases that they know her to be using;
RECENT ALIASES: Liana Hallik, Lyra Rallik, Kestrel Dawn, Tanith Ponta, Nari McVee
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Note that since Saw was originally a member of the Rebellion proper, he might have been the source of information about Jyn's other identities or she might be operating under a disposable identity that the Rebellion created.– ValorumCommented Jan 20, 2017 at 23:24
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I thought Jyn had acquired those fake names after she was abandoned by Saw? Commented Jan 28, 2017 at 8:33
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@Lupin - Presumably it would be moderately simple for an intelligence expert to track someone entering an area using one name but leaving under another. That's even assuming that she's not simply acquiring them from her rebel contacts (which would fool the Imperials but make it trivially simple for the Rebels to find out her aliases).– ValorumCommented Jan 28, 2017 at 8:37