I find it frustrating that the Sheriff's department appears to have missed the head wound. I'm thinking blood from the head wound ran down and soaked Tristan's shirt. And the Sheriff's deputies or park police (or both) thought the bleeding was from his chest/upper torso. I'm assuming Tristan was wearing a shirt because if he had been bare chested it should have been that much more obvious.
I read the ME's announcement before it was pulled (sorry, I didn't think to take a screen shot & post it). It was brief, essentially a list.
The cause of death was a gunshot wound to the head.
I don't remember the exact wording, but on the list there was a line for other wounds that could have contributed to death (or similar wording), and in the space next to it was none, or no, or similar.
Yes, he could have also been shot (or maybe grazed) in the upper torso/chest, but it would have been a more minor injury.
The head wound appears to have been missed, but hopefully not by the detectives/investigators before the body was taken away.