Following the revelation that Banjawarn was owned by the Aum, there was also speculation in 1997 that this event might have been the result of a test explosion of a nuclear device they had built. The event was determined to have had the strength of "a small nuclear explosion, perhaps equal to up to 2,000 tons of high explosives". It was known that Aum were interested in developing nuclear as well as chemical weapons, as they had recruited two nuclear engineers from the former Soviet Union and had been mining uranium at Banjawarn. However, the AFP investigation found no evidence of this or of any equipment that might indicate such research, and the Aum cult members were believed not to be in the country at the time of the event.