The RUC Chief Constable, Sir Ronnie Flanagan, and the DUP are at loggerheads over the origins of a document on the Kingsmill massacre in south Armagh in which 10 Protestants died.
The Rev Ian Paisley named 20 men in the House of Commons last month who he alleged were involved in the shooting. He said he was quoting from an RUC document.
Several men named in the document denied they were in any way involved in the attack. They could not sue Dr Paisley because parliamentary privilege protects MPs from being sued for remarks made in the Commons, but they threatened to sue him if he repeated his claims outside the chamber.
The RUC is investigating the origins of the document. Yesterday two of the men named, Mr Brendan Ferris and Mr Eugene Reavey, met Sir Ronnie Flanagan. They were accompanied by their solicitors and an SDLP Assembly member, Mr John Fee.
In a statement after the meeting, Sir Ronnie said: "We have absolutely no evidence whatsoever on which to connect these two men with the Kingsmill massacre, and there are no matters which are outstanding on which we wish to interview Mr Reavey and Mr Ferris.
"We are currently engaged in a very vigorous investigation to determine the exact origin of the document which Mr Paisley was reading from. I am satisfied at this stage of the investigation that it is not part of a detailed police dossier as has been alleged."
The statement was welcomed by both men. Mr Reavey said: "I am happy to hear the Chief Constable clear my name of these allegations and I would like Mr Paisley to do the same."
However, Mr Ian Paisley jnr said it was premature of Sir Ronnie to voice any opinion until the police investigation was complete. "There is no way my father would get up in the House of Commons and read from something that wasn't authentic."
Dr Paisley was due to be interviewed by detectives about the document later this week, although it was understood he would not be handing it over or naming his source. However, Mr Paisley jnr last night said his father would be reconsidering whether to be interviewed.
"If we think that the RUC has already made its mind up before the investigation is complete then my father will not make himself available."