Name: Horrocks
Died: 1744 (in TV series)Hugh Munro arranged a meeting between Jamie and a Redcoat deserter named Horrocks in episode S01-E08 Both Sides Now. Horrocks allegedly knew the name of the person who actually killed the soldier that Jamie was accused of murdering (Sergeant Wilkes).
Then when the meeting actually took place in episode S01-E09 The Reckoning, Horrocks told Jamie that it was actually Captain Jonathan Randall who killed the soldier. ARGH!
Horrocks shows up again in episode S01-E13 The Watch and tries to extort more money out of Jamie to make a fresh start in Boston, and even after he succeeds, he pushes him even harder for more money by threatening his family and saying he's the Laird and can raise his tenents' rents. Ian saves the day and handles the situation.
In the book, Horrocks is never seen, only mentioned, and he has a much smaller role than in the TV show.