The Galactic Alliance Department of Justice was formed in 28 ABY from its New Republic predecessor.
After the Solo-Niathal coup, the Justice Department handled the government's prosecution of the deposed Chief of State Cal Omas. However, Omas and his attorneys complained due to the fact that the Department did not charge him with anything until an extended period following his arrest. The matter never went to trial as Omas later killed himself.
In the aftermath of the Second Galactic Civil War, Jedi Grand Master Luke Skywalker was charged with dereliction of duty for allowing Jacen Solo to fall to the dark side of the Force and take over the Alliance. The trial ended in a 10 year exile for Skywalker unless he could find the reason Jacen fell to the dark side.
As the relationship between Chief of State Natasi Daala and the Jedi Order deteroriated, the Chief of State and was able to have Jedi shadowded. The Alliance Marshals were assigned as Jedi supervisors to make sure that Jedi Knights obeyed Galactic Alliance law.
The Justice Department pursued a criminal case against former Jedi, Sith, and Galactic Alliance Guard Lieutenant Tahiri Veila for the murder of Grand Admiral Gilad Pellaeon.
Later, the Justice Department ordered Trinnolt Makken to investigate the death of Acting Grand Master Kenth Hamner. Hamner had been killed in a lightsaber duel by fellow Jedi Master Saba Sebatyne. However, the Justice Department was unsure if a death during a lightsaber duel could be considered a crime to charge Master Sebatyne with.
- The Complete Star Wars Encyclopedia