According to the report (thanks to Izzy for the link!), KJ bled through his eyes, nose, and mouth, and there was a pool of blood below him. He had no cuts on his body, and it would seem that if he was killed by a fatal assault that skin would have been broken. I would guess that when the mat was put in a horizontal position (at which point his head, torso, and arms became exposed, when his body descended or was pulled out of the bottom of the mat) that some of that blood from the pool below him would have spread to parts of his body. As he was not cut, I cannot imagine from where else it would have come. If he had been bleeding before he entered the mat, one would expect blood to be found in many places, and not just in a pool below him. There was clearly not time for anyone who might have killed him to clean up all potential blood evidence of a crime -- of which I think there could have been none. (Also of note -- the 14 1/4" measurement of the aperture of the rolled mat is documented as an approximation, which would make it seem unlikely that it was actually measured before being unrolled.) Also, if the mat in which he was found was at the back-row of the rolled, vertical mats (as documented in the report), it seems impossible that he was rolled into a mat -- that would require that whoever did it would have had to have moved several mats weighing hundreds of pounds each. Totally implausible, to boot.
BBM for focus.
My scientific knowledge is limited, but given the fact that the body wasn't removed from the mat until a good 24 hours after the presumed time of death, also given the unseasonably warm temperatures, it seems to me that the blood would have been fairly dry/congealed, and not that easy to spread around.
But I don't know. However given the combined knowledge here at WS I'm sure someone else does who can (and will, I hope!) chime in.
Regarding where else the blood could have come from, I can imagine a scenario in which KJ enters the gym, gets into an altercation of some kind with the students who were already present, receives a bloody nose that leaves blood on his chest, and then is stuffed into the mat.
Because the nose is mostly cartilage, I'm not sure that type of injury would show up on an autopsy. But again, my scientific knowledge is limited.
Finally, blood was found in another place--the wall. The same blood that the sheriff's deputy stated they determined by sight was not related to their "crime" in any way. Since it wasn't tested, no one will ever know now whether it was KJ's or not.
Change of topic:
What really drives me crazy about this case is that the official explanation has never made sense to me. To repeat myself, if someone could show me a plausible reenactment of what happened, it would go a long way toward eliminating my doubts.
I acknowledge that others here on WS think it does make sense. I see logical arguments on both sides.
My point is, though, that I dislike even using the term "sides." This isn't a football game. We can all agree that someone's child died a horrible death. And we can all agree that we'd like to be absolutely sure of what happened.
So I'm grateful for the civil discourse.
And sorry for the ramble. /soapbox :blushing:
ETA: You're welcome for the link!