Special Branch agent Mark Haddock has been linked to the Shankill Butchers-style deaths of three teenage boys.
Police Ombudsman Nuala O'Loan has found evidence that Haddock is a suspect for the knife killings of John Molloy in 1996 and David McIlwaine and Andrew Robb in 2000.
She has now passed details of these cases to the PSNI's cold case review team.
These are the youngest alleged victims of the serial killer who was paid bonus payments of almost £50,000 by RUC and PSNI Special Branch on top of a £34,000 retainer from 1991 to 2003.
Mrs O'Loan decided not to name the victims or give details of the cases in her bombshell report as further investigation is needed.
A Police Ombudsman spokesman told the News of the World: "All of the murders have been passed to the PSNI for reinvestigation. There was limited intelligence about the five victims who we decided not to name and will not name."
But all of the victims are named in a fuller report running to over 200 pages which has been sent to PSNI Chief Constable Sir Hugh Orde and Secretary of State Peter Hain.
It also names SIX Special Branch informers, including Haddock, known as Informant 1, and the current UVF leader in south east Antrim, who were all involved in the Mount Vernon UVF unit.
In her damning dossier, an initial draft of which was first revealed by the News of the World in 2003, Nuala O'Loan referred to the other killings, the details of which are revealed here for the first time today (Sunday).
Her report stated: "The Police Ombudsman's investigators also identified less significant intelligence implicating Informant 1 in five other murders."
John Molloy, an 18-year-old Catholic was stabbed to death near his north Belfast home in August 1996.
Two men have been charged in connection with the murders of Protestants David McIlwaine, 18, and Andrew Robb, 19, in Tandragee in February 2000.
They were stabbed to death after falling out with drinking partners in a row over murdered UVF leader Richard Jameson, who was shot dead by the LVF.
