Afterwards, there were numerous speculations about the identity of the substance that was used to end the siege. Several chemicals were proposed, such as the tranquilizer diazepam (Valium), the anticholinergic BZ, the highly potent oripavine-derived Bentley-series opioid etorphine, another highly potent opioid, such as a fentanyl or an analogue thereof, such as 3-methylfentanil, and the anaesthetic halothane.
Following that, there were numerous speculations about the substance used to end the siege. Various chemicals were suggested, including the tranquilizer diazepam (Valium), the anticholinergic BZ, the potent opioid etorphine derived from oripavine, another highly potent opioid like fentanyl or a similar compound such as 3-methylfentanil, and the anaesthetic halothane.