When is Science New?
The Court of Criminal Appeals recently attempted to answer the question of when advances in science can be used to obtain relief after conviction. The usual situation is that a defendant was convicted years ago, and a key part of the State's case was forensic evidence. Since science (or at least our understanding) evolves, what was once well established may now longer be. Exhibit A is arson. In the past the so called experts relied on pour patterns and other indications which we now know exist in almost every fire. The problem is what to do with this new evidence.
The Court of Criminal Appeals has held that a defendant can obtain relief through habeas corpus when they can establish actual innocence based on newly available evidence. You cannot simply argue you were actually innocent; which would basically be retrying the case. You must establish there is new evidence available that establishes your innocence.
The court address the issue of "new evidence" in Ex Parte Spencer. There, the defendant presented a forensic visual expert (I haven't heard of one either - it sounds pretty cool), who testified the witnesses could not have seen what they claimed they saw. The court held that was not newly available evidence. They focused on whether the evidence as it originally existed could be retested or reevaluated. Since the scene had changed, and conditions were different, that could not be done..
In my opinion, the court fell into the trap of evaluating everything against DNA evidence. There is no doubt that everyone considers DNA evidence to be the gold standard, and as a result everything has been compared to that. In DNA testing the original evidence is retested, and there is no problem in doing so. However, not all advances in science fit easily into that categorization. Arson is one that immediately comes to mind.
Under the test adopted by the court, the advances in our understanding of fire dynamics would not qualify as new evidence. The scene would have long been destroyed, and pictures would probably not be sufficient. I'm sure there are other areas that will pose the same issues.
As long as forensic science is used in criminal cases, the courts must be open to reevaluating those cases when necessary. Science, and our understanding of different things is constantly evolving;. what we hold as truth today, may deem be discredited tomorrow. To allow a conviction to stand on discredited terrorist testimony can certainly not be considered fair or just.
