I would like for there to be some ambiguity in a character's death in a story I'm writing. Unfortunately, she lives in a universe with 3D scanners that can map out her corpse's molecular density and cellular structure (albeit with a low-ish resolution of 1 micron). The scans need to be precise enough that the data from one, combined with a machine to differentiate arbitrary cells from genetic data, can fully recreate a person (well enough that once printed, they don't feel any different than when they were scanned). The scanner isn't negotiable - I need it for other plot stuff. Obviously, in addition to the scanner, they have access to normal forensic techniques like blood testing.
Specifically, I'd like it to be easy to miss the fact that she was drugged and unconscious at the time of death, the explanation being that the drug had broken down in her system by the time she was scanned (1 day after her death, 2 days after the drug was administered to knock her out. These timescales can be slightly altered if necessary). The drug is fictional and its properties can be adjusted as needed to fit the story. The character's death was due to falling off a cliff, which may involve head trauma that could conceal structural effects of the drug in the brain. For completeness, the cliff is at a very low temperature (~ -20 degrees C), but the character was wearing a thermal suit, so this variable can also be tweaked if it helps.
My ideal scenario is that the scan shows something to make the coroner highly suspicious, but not enough to confirm that she was under, or if he IS certain she was unconscious, he isn't certain which drug was used. Is this plausible?