Yoshinori Ueda was born in 1955 in Yao, Osaka, the only son of a wealthy couple that owned a liquor store.
One day, he went to the veterinarian for a regular check-up and witnessed another person's puppy being put down with an injection of suxamethonium, a muscle relaxant.
Despite having no knowledge or experience in the trade, Ueda thought that he could make a lot of money from this business, prompting him to rent some farmland in Shiojiri and build a dog breeding ground and training school.
[1] Circa August 1991, Ueda befriended Koh Kashiwai, a 22-year-old construction worker from Osaka, to whom he offered a part-time job at his business.
[3] The next victim was 35-year-old Sanpei Fujiwara, an unemployed man from Osaka, whom met Ueda through a magazine for pet dogs and befriended him.
[3] In July 1992, he transferred 300,000 yen to Ueda's bank account, all the while planning to visit him at the training ground in Shiojiri.
[3] Suspecting that the recent disappearances might be connected, the National Police Agency formed a special unit to investigate them.
[3] Soon after his arrest, Ueda was put under intense scrutiny by the investigators, until he finally confessed to poisoning five of his prospective clients with suxamethonium.