Why would he have to wait on any forensic reports if he believes 100% that his client is innocent?
imoo
Any good lawyer would base the defense of his client best when most or all facts are known. The forensics would be the base to build a good defense, how else can he defend his client, he has nothing to start with, and he also needs the evaluation, which is common sense to do. If they have no conclusive evidence, that would not point to any side particular, than it is obvious he needs more info. I would have write more, but I'm tired and have to get up for work in 3 hours.