Quest Stages - TGTQ03 (Imitation Amnesty)

10 Speak to Olfrid Battle-Born
Olfrid Battle-Born, a wealthy Nord residing in Whiterun, has requested assistance from the Thieves Guild.
20 Steal the letter incriminating Arn
Olfrid Battle-Born has a good friend residing in Whiterun's jail who is slated for execution. In order to free him, a prisoner registry in the steward of Whiterun's quarters must be changed and a letter stolen from the Jarl's quarters in Dragonsreach.
30 Forge the prison registry
40 Return to Olfrid Battle-Born
200 Arn is now a free man and the Thieves Guild can now count on Olfrid Battle-Born as an influential ally in Whiterun.