I'm sure I'm not the first person to consider this, but ... RNA molecules can often be "evolved" in vitro to bind/inhibit target molecules with high specificit

I'm sure I'm not the first person to consider this, but ... RNA molecules can often be "evolved" in vitro to bind/inhibit target molecules with high specificity (e.g., https://en.wikipedia.org/wiki/Systematic_evolution_of_ligands_by_exponential_enrichment https://en.wikipedia.org/wiki/Systematic_evolution_of_ligand...) I imagine it would not be difficult to create RNAs that inhibit some essential human enzyme and then use the RNAs for targeted assassination. I mean, if you're doing an autopsy, you might run standard drug tests for poisons, but who's gonna screen for a highly specific RNA?