The father of another Protestant murdered by the UVF has called for wider scrutiny of the role of informers in murders.
Paul McIlwaine believes his son David and another Portadown teenager, Andrew Robb, were killed in February 2000 by a UVF gang that included an informer.
He was backed last night by SDLP Policing Board member Dolores Kelly, who said that the Police Ombudsman report on informer Mark Haddock has underlined a need to take a longer look at possible collusion in Mid Ulster.
Mr McIlwaine says the suspected informer has never been accused of the murders.
The man, a senior UVF figure in Co Armagh, was contacted by a police officer immediately after the bodies of the two boys were found by a roadside with their throats slashed.
Searches in the murder investigation turned up an apparent hit list with Catholic names on it and a witness said the document belonged to the UVF leader. That document was later destroyed by police.
A complaint made by Mr McIlwaine is currently being examined by the Police Ombudsman's office.
"We have given across information and there was evidence that would have merited arrests and criminal charges against the person we believe is an agent," he said.
"The information that was destroyed was linked to him.
"Hugh Orde stated this week that this is new policing and a new era, but it was his PSNI that was threatening a public interest immunity order to keep something secret when we took a case about this."
Dolores Kelly said the Police Ombudsman's investigation of Special Branch collusion should be extended.
She said the conclusions of the Haddock report "are absolutely damning, but it doesn't stop at a few bad apples in one barracks in Belfast".
"The whole list of murders stinks to high heaven of parallels with the Robb/McIlwaine murders in Tandragee," she said.
"Police handling of this murder inquiry urgently requires scrutiny, but the McIlwaine family is clearly convinced that a UVF informer was being protected and continues to be protected.
"It has always been a mystery how loyalist killers in the Lurgan-Portadown area, and indeed throughout the Murder Triangle, were able to operate with impunity year after year."