You say this is all Spike's doing, yet, you forget one thing. The claw marks don't match up! For one, Spike would have had no way of knowing the combination for the safe. Secondly, he probably wouldn't have been allowed to go into Pinkie's room, since he'd have to walk through the front door. Most families don't let you visit a room that belongs to someone who isn't home. That's breaking privacy, Mr. Justice. Thirdly, the claw markings, while they are indeed, claws, and Spike does, in fact, have claws, griffon claws are very distinct and discernible from every other type of claw. Not to mention, Gilda was confirmed to be the owner of the claw markings and blood found! There would have been no reason for the fight, if Gilda left empty handed. There would have been no reason for her to return, if she was empty handed.
There are too many inconsistencies, Mr. Justice. I'm afraid none of the evidence points to Spike.