Assistant Police Commissioner Malcolm Burgess does not believe a re-examination of evidence in the David Bain case will reveal anything new.
Mr Bain's defence team argues David Bain's father, Robin, was the killer, because two parallel lines in a photo of his thumb show he loaded bullets into the 22-calibre rifle used to kill members of his family in 1994.
Mr Burgess told Morning Report the police will look again at the thumb marks and test the theory, but he doubted whether anything will come of it.
He said he want to apply some science to see (the claim) holds up (or whether) the marks are an abrasion or something that was there temporarily.
In 1995, David Bain was found guilty of killing five family members, including his father Robin. That conviction was quashed by the Privy Council in 2007 and he was acquitted at a retrial in 2009.
Bain lawyer critical of police
David Bain's lawyer is critical of the police for saying two parallel lines in a photograph of Robin Bain's thumb do not prove he was the one who murdered the Bain family.
Michael Reed QC says the marks are gunpowder residue left when Robin Bain reloaded the rifle used in the killings.
However, police say his fingerprints show gaps where the markings appear, which could suggest they were small cuts.
But Mr Reed said the marks the police are referring to don't match the parallel lines shown in the photograph.
In a statement, he said the police are trying to weasle their way out of responsibility for the incompetence they demonstrated in the case.