That's an important point. No one found any blood splatter behind him at the site where he was found!
...any exit wound to the back of the skull.
There was no exit wound in the back of the skull, according to one of the EMTs who looked for one. If the bullet was shot from inside the mouth, as the autopsy report claims, there should have been a huge one! Plus, if the gun was placed in the mouth, the teeth would have been shattered, and no report of that.
...the forensic professionals who did the investigation.
Believe it or not, many of these "professionals" were compromised - to put it diplomatically. The autopsy in particular was bizarre. An X-ray of the skull, which would have shown a large exit wound if there was one, was either (1) not done or (2) made to get lost or disappear, probably the latter. A good guess is that it got lost because it showed something that was grossly inconsistent with the "findings" in the written report.
From the Starr report:
"Dr. Lee stated that one photograph of the scene "shows a view of the vegetation in the areas where Mr. Foster's body was found. Reddish-brown, blood-like stains can be seen on several leaves of the vegetation in this area." He also noted that "[a] close-up view of some of these blood-like stains can be seen in [a separate] photograph."
Other parts of the report detail blood splatter on Foster's hands, face, and shirt.
There was no exit wound in the back of the skull, according to one of the EMTs who looked for one.
From the Starr report:
"...upon the autopsy report and photographic evidence that there was bleeding beneath the scalp about the gunshot exit wound and beneath the fractures of the back of the skull."
Believe it or not, many of these "professionals" were compromised - to put it diplomatically.
Proven? Or wishful thinking?