I don't know the case.
But this dude knew how to kill and kill fast...
He knew where to strike to bring about death quickly.
That's my feeling.
He possibly also knew how to do it without causing blood to spatter on himself.. but the crime scene is a whole other story.
But a footprint was found, a latent footprint.
Now a whole series of them..
He was technically adept.
At killing.
I'm not sure how he could have learned that from books..
Maybe it's possible.
Nor was he described as breathless when leaving.
How could he have known?