In Karam's booklet "Innocent!"he refers to the fingerprints in blood on the rifle.He sums up by saying
"This material[blood or whatever,my words]was not tested at all prior to trial,but DNA analysis since then has shown the material not to be of human origin but some other mammal,probably rabbit or possum and therefore totally unrelated to the killings"
This is where memory comes in.I am certain I have read where that DNA analysis showed nothing of the sort.
Check Hershel's (ESR) and Kim Jones evidence
Joe Karam made much mileage and probably destroyed Milton Weir's police career by claiming that the lens that Milton Weir claimed he could see in a photograph of the crime scene in Stephen's bedroom was a specular effect. Karam's determination was so great that he had Milton himself conceding he must have made a mistake.
Milton Weirs evidence proved correct. It has since been found through more improved techniques of photo analysis, that Milton was in fact correct and the image is of the lens and is not a specular effect at all. The news item for this can be found Here