Not exactly. There are rules in place for destructive testing. Usually, the prosecutor notifies the defense attorney that they want to conduct a destructive test (assuming it isn't time critical). The defense is given a chance to examine the evidence first, observe the testing, and otherwise take whatever steps it wants. If that isn't practical, the court will look at the situation and decide whether the prosecution (which in this case includes the police and the labs) acted in good faith when destroying what the defense claims is potentially exculpatory evidence and whether there's any reason to believe the defense was harmed. Assuming there are good quality pictures, it is going to be hard for the defense to show harm in a typical case.Graham F wrote:I believe what Sharon was alluding to was, that there would be a high probability that to conduct a DNA analysis of a latent that had been identified would result in the destruction of the original latent evidence. This is something the defense attorney would undoubtedly jump on, in that there is no latent evidence remaining for them to scrutinize with their own expert, if they so wished. You could photograph the latent first before its destruction by the subsequent DNA analysis and just retain the photo as the only evidence. This just provides another string to the bow of the defense.
But again, I was thinking about this more as a possibilty for a study attempting to validate fingerprint matching using a second type of analysis on the same evidence, rather than as something ready for routine use in the crime lab. DNA testing is darned expensive, and I had gathered from the articles that testing of prints was still very experimental. I hadn't realized the problems were quite that extensive, I'd assume some of them could be controlled in a study if the experimenter generated the prints (attempting to match the quality found in typical crime scene work.)
Not to underestimate the inguenity of my fellow-attorneys, but most of these questions have been resolved in the DNA cases -- mixed sources, sources contaminated by other sources at the scene -- I suspect the whole mess will get tossed to the jury to sort out after the dueling experts testify. If this became a commonly used technique, the jury would have to deal with the inconclusive or inconsistent results the way it resolves them in cases where other evidence is in conflict -- witness says defendant shot the victim, defendant is arrested within minutes and tests negative for GSR, for example.Graham F wrote:What if the latent is from a commonly handled item? If the DNA does not match the suspect does that mean that the latent has been misidentified? (Inwardly laughs to himself).