Joe Karam made complaints about the destruction of blood samples taken from Robin's hands, accusing the police of destroying evidence that could have proved his case that Robin was the killer.
Detective Mark Lodge said there was a smear of blood on the heal of Robins left thumb on the inside of his hand and there was also a small smear of blood on the little finger. These were tiny specks of blood and as forensic scientist Mr. Henstchel said there was not enough for testing. These specks of blood that were also on several items around Robin’s body were consistent with the spatter of blood from his head wound when he was shot.
Detective Sergeant James Doyle testified that 14 years ago the ESR looked at the slide of samples of blood from Robin Bain’s hands and was advised that at that time there was nothing that they could do with these samples because of their size, and that was a contributing factor when ordering the destruction of those samples. It is probable that, given the large amount of evidence pointing to David Bain as the killer the police decided that they didn't really need any more evidence and so the blood samples were superfluous.
The police officer later in charge of the Bain case, Detective Chief Inspector Peter Robinson, testified that, in hindsight, it would have been beneficial to test the blood specks and fingernail scrapings found on father Robin Bain's hands. The fingernail scrapings were disposed of by the police but if they were kept then with the improvements in DNA testing they may have been able to be successfully tested and, rather than implicating Robin could have further implicated David Bain instead. The fact is that Robin had very little blood on his hands and it is evident that whoever killed Stephen would have ended up with blood soaked hands. The police said there was dirt in the creases of Robin Bains hands indicating that he had not washed them.
This so called 'evidence' is conflicting because a 21st century testing of the blood on Robin's hands and the scrapings under his fingernails could have implicated either David or Robin but we will never know. The samples were destroyed not because the police sought to destroy evidence incriminating Robin, but simply because they could not be tested and also most probably because further evidence was not needed to secure a case against David. More reading found HERE