Originally, Aum planned to massacre citizens by spraying botulin, the most lethal natural poison to humans, from buildings and modified delivery vans. Aum’s team of young scientists cultured and experimented with biological toxins, including botulin, anthrax, cholera, and Q fever. The transition to chemical weapons came after biological attacks failed. Investigations and raids after the subway attack showed that Aum was capable of producing thousands of kilograms of sarin a year, according to the
Center for Disease Control (CDC). The cult had also acquired a Russian military helicopter that could have been used to distribute the gas, the police said.
Initial plots failed to produce the deadly chaos that Aum wanted, although one incident in June 1993 in which Anthrax spores were released from a Tokyo building caused a foul odor in addition to the deaths of some birds, plants, and pets. According to the CDC, Aum sent a fact-finding team to Zaire to study and collect Ebola virus samples in 1993. Aum reportedly sprayed some of the failed batches of biological weapons in the areas surrounding U.S. military bases in the early attempts involving botulin, according to the
New York Times. After the subway attack, the State Department says that Japanese authorities reinvestigated and found Aum responsible for a mysterious attack—that later proved to be sarin—on a residential neighbourhood in 1994 that killed seven and injured over one hundred people