How long would they remain detectable by an autopsy in a county that didn't even want to spend $5k on DNA testing? How long was the body decaying before discovered. I do agree about the necrotizing venoms. But consider a black widow. You could be incapacitated, rendered helpless for a day or so, and become sufficiently dehydrated to be essentially delirious after recovering from the bite proper. That would leave you in a state that, without assistance, you'd not die from the bite, but from starvation/dehydration several days later. How long is the toxin in the body?

> All of this would show up in an autopsy

Not necessarily. The toxin could have been ingested, especially if it was something man-made rather than natural. Many would have left recognizable signs, but others you'd have to know what signs to look for and/or do a specific test. Whatever it is might even have cleared his system (it takes a while to become that emaciated) but not before doing some kind of neurological/motor damage.

Depends on the state of decomposition as to what they would find in the autopsy, but I would generally agree that invenomation is unlikely as it wouldn't explain the emaciation (they could be coincidental). Found in a tent in FL... I don't want to imagine that smell. It's also possible they found anomalies or issues but were not able to tie them to the death (I imagine the autopsy is confidential).