David Bain does not know whether to laugh or cry about so-called "new" evidence said to clear him of murdering his family but which went unnoticed 19 years, says supporter Joe Karam.
Mr Karam said he was "embarrassed" he had the information in front of him and never noticed it.
Last month, claims were made that parallel markings on Robin Bain's thumb were consistent with his having fired a gun on the morning of the killings, in June 1994.
The marks matched those made by gunpowder residue when loading the magazine of a rifle shortly after it had been fired.
Police rejected the claims. Assistant Commissioner Malcolm Burgess said Robin Bain's fingerprints showed patches on the thumb, suggesting cuts from "handyman" work.
"Marks on a photograph can always be open to several interpretations by experts ...
Examination of the original photograph does not give any definitive indication of what the marks could be," he said.
But yesterday, Mr Karam said a second set of photographs of Robin Bain's thumb further supported the theory. That set of fingerprints was taken on June 21, 1994, the day after Robin Bain died, and were "perfect" prints with uninterrupted ridge lines.
The prints police had referred to were taken on June 22, 1994, after Robin Bain's body had been moved in and out of refrigeration in the mortuary.
Mr Karam said a fingerprint expert confirmed that the change in the body's temperature would have caused condensation on his hands.
When the second set of prints were taken, some ink would have been repelled by the presence of moisture, causing "blotchy white marks".
Yesterday, a fingerprint and forensic expert the Herald spoke to said the condensation theory was "possible".
But copies of fingerprints, such as those relied upon by Mr Karam, "leave a lot to be desired".
Mr Karam said David Bain was torn over the information.
"He doesn't know whether to laugh or cry ... he cries that evidence of his innocence has come up after being physically lost from his father's body."
Mr Karam said the police, in rejecting the theory and publicly releasing the second thumb print, had "blatantly misled" the public.
Last night, Mr Burgess said: "It would have been helpful if Mr [David] Bain's supporters raised these issues direct with police for clarification before launching them into the media with claims of wrongdoing or incompetence."
He said the fingerprints of Robin Bain taken on June 21, 1994, were taken by a detective, and a police fingerprint expert determined they were not of adequate quality.
The expert took two further sets of prints the next day.
Police yesterday said they would apply for access to all of the original prints, which were held by the court and not by police.
Mr Karam told Radio New Zealand this morning he was "surprised" police were were going to court.
"Because I'd be very surprised if the originals of these are in court. And if they are going to the court, I imagine the court will seek the approval of David Bain's legal team for the police to be uplifting exhibits of the court if they are there, and we'll find that out."
He said police were "being mischievous again, really".
"Because what they should actually acknowledge is that the fingerprint I released yesterday proves categorically that they are not cuts.
"It doesn't really matter what they find on these other ones afterwards, because the first ones - the rich detail, as I say, is uninterrupted. There is no damage to it."
Joe Karam says:
The marks on Robin Bain's fingers cannot have been cuts because they were not present in the first set of fingerprints taken after he died. Police have misled the public by only releasing the second set of prints, which show the marks, deemed to be cuts.
The second set of prints are accurate. The first set of prints was taken by a detective, the second by a fingerprint expert who determined the first set were not adequate. Police are applying to the court for the originals, which they will re-examine.