Before we jump to that conclusion, several forensic experts who admittedly have only looked at the photos are questioning that due to the closed cranial sutures which are never seen on adolescents. They say the skull is more likely that of someone at least 25 years or more old. I tend to agree with that conclusion based on that observation alone.
The overall size (compared with nearby objects (camera, water bottle, hand, boot, etc.) in the frame does not appear to be large enough to be adult.
Granted, we don't have forensic measurements, X-rays, and exams, but, under these political conditions and given the behavior history of LEOs in this case, I'm not prepared to accept their field statements as gospel, either...
As someone else mentioned, regardless of size, a recently-deceased individual warrants a full homicide examination -- not a brush-off like, "That's just an adult skull".
(BTW, FReepMail for you coming up...)
FRegards,
TXnMA