Convicted loyalist murderer Michael Stone is being questioned by the PSNI at Antrim police station after he was arrested in London two days ago.
The man who killed three mourners at a funeral at Milltown Cemetery, Belfast, in 1988 was brought back to face questioning in Northern Ireland.
It is understood Stone voluntarily walked into a police station in London yesterday and was flown to Belfast accompanied by detectives from the PSNI.
Stone served part of a life sentence for the murders at Milltown when he fired shots and threw hand grenades into a crowd of mourners attending the funerals of three IRA members shot dead by the SAS in Gibraltar.
He was released early in June 2000 under the terms of the 1998
Belfast Agreement, but later distanced himself from from ex-associates because of tensions inside the Ulster Defence Association.
He has been questioned a number of times in the past by police after surrendering himself in Northern Ireland but has never faced any new charges.