[@Bounce] Entry and Exit wound on the fourth(?) shot gives away the height and position more easily, along with the close range execution done after. Unless he was really lucky with blood splatter or took time to clean up after himself there's Heelys marks all over the table and your palm-heel's potentially going to leave some pretty interesting bruising post-mortem. Someone with the know-how could make a decent guess for weapon, position and size off of the decapitation itself too. He was done in thirty minutes, didn't miss a single shot and killed every gunman in the room before they could return fire, plus the knife's not bloodied.

So you've got size, weaponry, the high degree of training and also a decent guess at the age unless you're a little person who particularly enjoys Heelys footwear. Fingerprints and DNA would've been useless anyways, he's likely not in any databases, certainly not under an identity of any significance and it'd be ridiculous for them to run a paternity test off of Bruce Wayne just in case. XD 

Then again I'm tired and been sick as a dog for two or three days, so feel free to ignore my rambling. 

I did very much enjoy your vulnerability moments though, very good job.