Belfast, Northern Ireland (CNN) -- One of Northern Ireland's biggest and most expensive terrorist trials ended Wednesday with 12 of 13 defendants cleared of all charges against them, including murder, kidnapping and having guns.
The suspected members of the pro-British or loyalist paramilitary group the Ulster Volunteer Force (UVF) were being tried at Belfast Crown Court on the word of two self-confessed UVF members, brothers David and Robert Stewart.
Nine of the accused were acquitted of murdering paramilitary leader Tommy English in October 2000. The 40-year-old Ulster Defence Association (UDA) member was gunned down in front of his wife and young children on Halloween night during a bloody feud between rival groups.
The Stewart brothers admitted to their part in English's killing and agreed to testify to get a reduced sentence. The so-called "supergrass" non-jury trial started in September 2011 but Wednesday ended with the judge branding the prosecution witnesses "unreliable."
Justice John Gillen said the Stewarts were "ruthless terrorists who had lived on a daily diet of lies."
Up to 200 people including armed police were in the courtroom, and supporters cheered when the not guilty verdicts were read out. A spokesman for the UVF-linked Progressive Unionist Party, Ken Wilkinson, said the proceedings had been "a show trial" which had cost "in the region of 20 million pounds" (approximately $31 million).
He added, "The supergrass system failed in the 1980s and it has failed today." Supergrass is a slang term for an informer.
The one defendant convicted of any offenses was found guilty of possession of a sledgehammer intended for use in terrorism and intending to pervert justice.
One of those cleared of murder is alleged loyalist leader Mark Haddock, who had been accused of ordering the death of UDA boss English. Haddock, aged 43, had been named as a police agent in a 2007 report on the UVF by former Northern Ireland police ombudsman Nuala O'Loan. O'Loan said a UVF gang based in the Mount Vernon estate in north Belfast had been involved in up to 15 murders and that the Northern Ireland police special branch unit had allowed informers within the Mount Vernon group to act with impunity.
The Ulster Volunteer Force and Ulster Defence Association were responsible for the killings of hundreds of people during the conflict between pro-British and pro-Irish forces in Northern Ireland over a 30-year period known as the Troubles. Most of their victims were Catholic civilians. The groups have remained active since the signing of the Good Friday peace agreement in 1998.