A former loyalist paramilitary commander turned supergrass has pleaded guilty to 200 terrorist offences, including five murders.
Relatives of Gary Haggarty's victims watched on as the ex-chief of the Ulster Volunteer Force's notorious north Belfast Mount Vernon unit repeatedly answered guilty to the litany of charges put to him in Belfast Crown Court.
The pleas marked a significant stage of the long-time police informer's agreement to give state's evidence against fellow terrorists.
As well as the five murders, the 45-year-old, who is currently in protective custody, admitted five attempted murders, including against police officers; 23 counts of conspiracy to murder; directing terrorism; and membership of a proscribed organisation.
He also admitted assisting offenders involved in a murder bid on fellow UVF terror chief and police informer Mark Haddock.
On top of the 200 guilty pleas, Haggarty acknowledged responsibility for 304 other more minor offences. Those were not listed as formal charges on the bill of indictment but will be taken into account by the judge when he is sentenced.
Haggarty was interviewed more than 1,000 times by detectives in one of the biggest and most complex cases ever undertaken in Northern Ireland.
The catalogue of offences stretch over a 16-year period from 1991 to 2007 and include the loyalist murders of John Harbinson, Sean McParland, Gary Convie, Eamon Fox and Sean McDermott.
Haggarty is expected to receive a heavily reduced sentence in exchange for his cooperation with the authorities.
Outside court, Mr Fox's son Ciaran broke down as he described his feelings.
"It's just hard sitting in a courtroom watching a guy admitting to murdering your father," he said.
Mr Fox said the fact Haggarty was an informer when the offences were committed raised serious questions for the authorities.
"The police knew what was going to happen and took no action to stop it," he claimed.
"Basically he was just a hitman - he killed at will."
He added: "Police knew my father and Gary Convie were both going to be murdered and they sat back and let it happen and that's hard to swallow.
"I don't care about the UVF, they'll meet their maker some day - the police, the people who were in authority to protect and serve, they didn't protect my family."
It is understood Haggarty has made allegations against 14 fellow loyalists, for crimes including four murders.
He has also given evidence in relation to alleged criminality by two former Royal Ulster Constabulary Special Branch handlers who worked with him when he was an informer.
His own lengthy charge sheet also includes aiding and abetting murder, kidnap, possession of firearms, ammunition and explosives as well as hijacking, false imprisonment, arson, intimidation and conspiracy to riot.
But he could walk free after his sentence hearing in September, given he has already served three years in custody - the equivalent of a six-year sentence.
In the interim, prosecutors will decide how to proceed with the evidence he has provided.
The content of his interviews amounts to 23,000 pages of transcribed evidence.
There was a significant police presence in and around the court for the high-profile arraignment hearing.
Haggarty, who is believed to be living at a secret location outside Northern Ireland, was escorted into court through a side door by two specialist police officers.
He was initially arrested in 2009 and charged with the murder of Mr Harbinson.
He then indicated his willingness to turn state's witness and subsequently signed an agreement to become an assisting offender under the terms of the Serious Organised Crime and Police Act (Socpa).
The terror boss, whose address was formally recorded on the indictment sheet as care of a Belfast police station, stood in the dock dressed in a grey suit during the hearing before judge Mr Justice Treacy.
Mr Fox expressed doubt Haggarty would ever end up in the witness box, alleging vested interests would thwart it.
"This goes right to the top, there are too many people going to get their hands burnt," he said.
"He's done wrong, his hands are deep in blood along with people he's going to expose and because of who he's going to expose I think it's not going to finish."
Mr Fox said it was hard to take that Haggarty would get a reduced sentence.
"He was bold as brass answering them (the charges), it was water off a duck's back. That's the hard part, just knowing he is going to walk a free man.
"The charges he is charged with, in an ideal world that man shouldn't see daylight."
After the hearing, Detective Superintendent Richard Campbell, from the Police Service of Northern Ireland's Serious Crime Branch, said the guilty pleas marked a "milestone" for the victims and their families.
"It has been a very long, arduous and painful process for these families and I hope today's proceedings have made a significant contribution to the process of ultimately bringing closure to all the families of the victims of Mount Vernon UVF during that time," he said.
"The PSNI remains committed to moving forward and working with the PPS (Public Prosecution Service) in relation to the next stages of the investigation into Mount Vernon UVF and others who were involved with committing these offences.
"My detectives have worked hard over the last seven years to bring justice. I understand the frustrations of the families over the length of time this has taken but I have always said that it was important to take the time to get it right."