Ema Skye did nothing of the sort. If she did, we'd find hairs belonging to Manfred von Karma on her items as well.
Instead, I believe it was in fact, Manfred von Karma who has committed this crime. Right here with me, I hold a torn cravat. Now, as aesthetically pleasing, and downright amazing as a Cravat is, it is unfortunately not a very well adopted tie these days. Only one other man in the prosecutor's office wears a Cravat, and it is none other than Manfred von Karma. This was found with the victim.
I also present to you a keycard. Such an item allows it's user to enter the courtrooom at any time of day or night, for that matter. One is given to each Prosecutor.This one in particular is assigned to Manfred von Karma.
Using these two pieces of evidence, it is easy to deduce what truly happened at this scene.
Mia Fey and Manfred von Karma got into an altercation, eventually escalating to a point where Manfred grabbed a knife and attempted to stab her. His first try was unsuccessful, resulting in this torn cravat. He then stabbed her, and framed Miss Ema Skye.