Mr Hamill, a Catholic, died in May 1997, nearly two weeks after he was beaten by a loyalist gang in Portadown, Co Armagh.
There were claims that the RUC, sitting in a vehicle, observed the attack but failed to intervene, and that one or more police officers colluded in hampering the investigation.
The Robert Hamill inquiry will be chaired by Sir Edwin Jowitt, a retired member of the High Court of England & Wales. He will be joined on the inquiry panel by Sir John Evans, former chief constable of Devon and Cornwall, and Reverend Baroness (Kathleen) Richardson of Calow, former Moderator of the Free Churches' Council of England & Wales.