The victim drank a bottle of Oronamin C, a vitamin energy drink,[1] that was left on top of a vending machine in Fukuyama, Hiroshima Prefecture.

[3][5][6] At the time of the murders, Ohtsuka Pharmaceutical, the company which made Oronamin C, had a buy one, get one free promotion of the drink to combat low sales among young people.

[6] On September 27, the National Police Agency declared preparations for a nationwide campaign to prevent further poisonings, which included leaflets distributed throughout Tokyo.

[8] Japanese Soft Drink Bottlers Association spokesman Takeo Mizuuchi shifted blame onto victims, expressing how customers should notice broken seals and stating that "if only consumers were more cautious, they would have seen that some tampering had been done."

[6] The Chicago Tribune reported that experts in various fields at the time of the murders speculated them to be a manifestation of Japan's orderly, intense and work-oriented society.

[5] Additionally, Susumu Oda, a mental health specialist at the University of Tsukuba, suggested the crimes to be motivated by adrenaline rushes and a sense of superiority in imagining victims struggling.

[2][6] By December 8, the spree killed at least ten people and made 35 seriously ill.[2] In 2012, CBC News reported the death toll may have been as high as twelve, which would make it possibly the deadliest product-tampering case in history.

[1][5] The case had no DNA evidence and the culprit was never caught, although if apprehended, they could still be held legally liable, as Japan abolished the statute of limitations for murder in 2010.

[9] A potential copycat crime happened in December 1985; in Mie Prefecture, containers of milk served in schools were tainted.