Ok, I understand the gist of what you're getting at about GHB detection presenting difficulties, but I don't see how the body floating in water would be particularly relevant (unless, of course, it was so severely decomposed that almost any internal evidence would be gone, whether GHB or whatever).
Most of what you posted is general issues with GHB detection, but not specifically related to a body in water, unless I'm misreading it. Assuming the conditions of a corpse are such that GHB would be detectible, I don't understand how floating in water--water that is on the body--would wash out the inside of the body of GHB evidence. After all, skin functions as a barrier to the outside environment, even after some degree of decay. It's not as if the water a body is floating in somehow flushes through the body's system, or am I wrong? I don't see how the organs, veins, etc, inside the body would even come into contact with the water unless the body's decay reached those parts.
But I'm certainly no expert on such things. I'm just basing these ideas on a combination of logical analysis (my version of it, anyway
) and facts from previous cases in which substances were able to be detected in bodies that were in water for extended periods of time.
What I'm really trying to ask, in a long-winded way, is: by what mechanism or action would the water in the cistern clean out evidence of a drug from
inside EL's body?
(BTW, they identified her from markings on her body, so her skin was presumably still intact)