If I had to guess, it is probably waiting on toxicology.
Here is my scenario for how to get broken bones diy: tie neck to bunk from top bunk and then bunch yourself up as much as possible and leap towards opposite wall. But much more likely it was the second shooter on the grassy knoll.
So it’s not released. It’s just leaking.
For the conclusion of the autopsy and the results of the exhaustive FBI investigation just substitute the right name, “Oswald Acted Alone”.