The Police Ombudsman's three-year inquiry, prompted by the McCord case, found that senior RUC officers protected UVF informants and prevented them from being fully accountable to the law.
Mrs O'Loan's investigation covered the years between 1991 and 2003 during which 10 murders, including that of Mr McCord jnr, were committed.
In addition, more than 70 other serious offences which are linked to police informants were also recorded.
Throughout the report, repeated reference is made to a known UVF figure called "Informant 1" whom reliable sources have identified as Mark Haddock (37, above).
He is currently serving a 10-year sentence for causing grievous bodily harm to the doorman of a club in Monkstown on the northern outskirts of Belfast.
Last May he was shot a number of times in Newtownabbey, Co Antrim while on bail and was critically injured.
Raymond McCord jnr
The 22-year-old former RAF member was found beaten to death at Ballyduff quarry on the outskirts of north Belfast on November 9th, 1997.
Mrs O'Loan's report states that Haddock ordered him to be killed following a dispute over drugs.
The report quotes evidence from the case senior investigating officer who said that Mr McCord jnr was caught with a consignment of drugs and that Informant 1 lost £50,000 worth of drugs because of this.
It further states that special branch passed on intelligence about the case to CID at the time.
One suspect in the killing is referred to in the report as "Man D", a prisoner on leave from the Maze prison. However, there was a failure to examine the suspect's clothing at the prison and a vital forensic opportunity was lost.
Haddock and others were arrested and questioned about the killing but were released without charge.
The report also points to the destruction of exhibits including a car thought to have been used in the McCord killing. Mrs O'Loan did not find evidence to support the claim that police knew of the plan to kill Mr McCord jnr.
Peter McTasney
The 26-year-old voluntary worker was shot dead at his home in the Bawnmore area of north Belfast on February 24th, 1991.
Haddock was arrested and questioned 19 times by his RUC "handlers". Mrs O'Loan reports that they "babysat" him through interviews to ensure he did not incriminate himself. She further reports that the interview notes did not reflect the interview and that he was released without charge.
Although two men were subsequently convicted, special branch did not tell the DPP of the involvement of a police informant.
Sharon McKenna
Ms McKenna was a 27-year-old Catholic taxi driver who was shot dead on January 17th, 1993.
She was shot dead while visiting a Protestant pensioner at his north Belfast home.
Two men called to the door and forced their way in when the pensioner opened it. They demanded the keys to her car and, as she turned to lift them from the fireplace, they shot her in the back.
In interviews with Mrs O'Loan's investigators, senior RUC officers said Haddock had told them he was one of the gunmen. This is supported by "high grade" information.
It said authorisation was given by special branch to arrest Haddock on January 19th, 1993. However despite this, he was still met by his handlers the following day, raising serious concerns about the integrity of this meeting.
Haddock was arrested and interviewed 37 times over the course of six days, on some occasions by his "handler". The report states that another officer present claimed he felt like "a gooseberry" in that he knew his RUC colleague was interviewing his own "source" and that nothing of any value would emerge from the questioning. No one has been charged with the murder and Haddock's monthly informant's pay was increased from £100 to £160 despite the fact that he remained the main suspect.
Seán McParland
The 55-year-old father of four was shot dead in north Belfast on February 25th, 1994 as he babysat his grandchildren in his daughter's house. He died the following week from his wounds.
The Police Ombudsman's investigators uncovered information pointing to a planned shooting in north Belfast and to intervention by the RUC to stop it.
Police also received information regarding Haddock's involvement in the planned attack which was called off when the police presence was spotted. Mrs O'Loan reports that other evidence, seen by her investigators, shows another informant carried out the killing and that Haddock was also involved.
Gary Convie and Eamon Fox
Mr Convie (24), a father of one, and Mr Fox (44) a married father of six were shot dead while eating lunch at a building site near the Tiger's Bay area of north Belfast in 1994.
Both were well-known GAA figures from Co Armagh.
Haddock was suspected of the murders and arrested. Mrs O'Loan reports that the gunman was said to have been wearing a "goatee" beard at the time of the attack. Haddock too had a "goatee" beard but was given time to shave it off while in custody.
She found that no identity parade was organised and that Haddock was released without charge.
A former British soldier was later convicted of the killings. He had been dismissed from the Royal Corps of Signals.
Gerard Brady
Mr Brady was a 27-year-old father of two and worked as a taxi driver and plumber. He was shot dead by two men who were passengers in his car on June 17th, 1994.
They forced him to drive to Carrickfergus in south Co Antrim were he was shot in the head.
Mrs O'Loan's investigators found that the RUC had intelligence linking Haddock and another police "source" to the killing. They state also that ballistic tests have established a connection between the gun used and Haddock and other informants.
John Harbinson
He died after he was handcuffed and beaten by a UVF gang based in the Mount Vernon estate in north Belfast on May 18th, 1997.
Mrs O'Loan reports that RUC special branch had a "significant amount of high-grade intelligence" about the four main suspects for the murder, including Haddock, but did not pass on this information to the police officers investigating the murder.
It also said Special Branch had information that those who had carried out the murder had fled to a location in Co Down where they were "safely ensconced".
But again, they did not pass this information on and forensic opportunities were lost.
Thomas Sheppard and Thomas English
Mr Sheppard (below) was a 41-year-old UVF member who was shot dead in a pub in the Balee area of Ballymena, Co Antrim on March 21st, 1996.
Mr English, killed on October 31st, 2000, was a prominent loyalist in north Belfast who was shot dead as part of a loyalist feud.
The ombudsman's report states that investigators have seen information which links Haddock to both murders.
Mrs O'Loan's report goes on to detail its findings about Haddock's involvement in attacks on Sinn Féin offices in Monaghan and on a bar in Portadown, Co Armagh. The report also deals with evidence linking Haddock to drug-dealing and punishment attacks and to special branch "blocking" the searches of locations where UVF weapons were thought to be stored.