Nine defendants in the UVF supergrass trial have been cleared of the murder of UDA leader Tommy English 12 years ago.
Loyalist leader Mark Haddock had been accused of being the UVF commander responsible for the murder on Halloween night in 2000.
UDA chief English, 40, was gunned down in his house in Newtownabbey, Co Antrim in front of his wife and three young children during a bloody feud between the Ulster Volunteer Force (UVF) and the UDA.
Sitting for 21 weeks, the trial at Belfast Crown Court was one of the longest in Northern Ireland's legal history and is set to be one of the most expensive.
The prosecution case against 13 men in the five month trial at Belfast Crown Court was based on the testimony of two brothers and self-confessed UVF members who turned state's evidence in return for significantly reduced jail terms.
Window cleaners Robert and Ian Stewart alleged that nine of the defendants were involved in the murder.
Four others stood accused of lesser offences including assisting offenders, perverting the course of justice, and meting out paramilitary beatings.
A 14th man walked free from court last month after judge Mr Justice John Gillen, who sat without a jury, ruled that he had no case to answer.
Mr Justice Gillen delivered a withering assessment of the evidence provided by the two brothers, saying Robert and Ian Stewart's testimony was "infected with lies".
The judge said he was not convinced that men he described as "ruthless criminals and unflinching terrorists" had turned over a new leaf and decided to tell the truth.
"These were the same men wearing new suits," he said.
The so-called "supergrass" trial has been controversial, with supporters of the accused likening the case to high profile trials in the 1980s, which saw both loyalist and republican paramilitaries jailed on the evidence of former colleagues who turned state's evidence.
There was a major security presence today with armed police in court and the public gallery was packed.
There was applause from the public gallery and muted cheers at the verdicts.
The judge permitted the defendants, apart from Neil Pollock and Haddock, who remain in prison, to walk from the dock.
After embracing and shaking hands, they emerged from the court room to be greeted by loud cheers from family and supporters waiting outside.
In delivering judgment, Justice Gillen insisted the verdicts were not a reflection on the practice of relying on the evidence of criminals who have turned state's witness, but were based on the unreliability of the Stewart brothers.
Haddock and 11 of his co-accused were cleared of all charges.
Only one defendant, Neil Pollock, 36, from north Belfast, was found guilty.
He was convicted of perverting the course of justice and possessing an item likely to be of use to terrorists - namely a sledgehammer.
Crucially, the evidence on which those verdicts were based did not rely on the testimony from the Stewart brothers.
The men acquitted of English's murder were Haddock, 43, David Miller, 40, Alex Wood, 35, John Bond, 45, Darren Moore, 42, Ronald Bowe, 35, Samuel Higgins, 36, Jason Loughlin, 36, and Philip Laffin, 34.
They were also cleared of other charges, including false imprisonment, kidnapping, UVF membership, wounding, possessing firearms and hijacking.
The others acquitted were William Hinds, 47, David McCrum, 32, and Mark Thompson, 37.