Liam Jones
Liam Jones is a Live Sample Security Engineer working for Arque Corporation, with an office at Arque East (inside the Liam Brothers mine).
Liam's badge is found in Estranged: Act I at Arque West (it is used to open the cell holding George Richmond), and his main story is discovered via audio diaries and emails in Estranged: The Departure.
Liam has an assistant called Hawthorne, and often misplaces his security badge (a fact which allows the Fisherman to free George Richmond and gain access to Arque East).
Events of Estranged: Act I
Liam's keycard is found in Arque West, and is used to open the cell holding George Richmond. Liam does not feature further in Act I.
Events of Estranged: The Departure
The Fisherman comes across the office of Liam Jones, situated outside of Arque East (inside the Liam Brothers mine). Audio diaries, emails and other media can be found in and around the office telling the story of Liam, but Liam himself is not present (and his status remains unknown).
The audio diaries provide hints about the origins of the Infection, and based on these it is possible that Liam himself is infected (however this is is speculation and not confirmed within the game).
List of appearances
Estranged: Act I (first appearance)
Estranged: The Departure