Gen Sekine and ex-wife Hiroko Kazama are known as the Saitama Dog Lover Murders due to the connection between the victims and the dog-breeding business the couple operated. The two were renowned dog breeders in their country and ran a kennel. They were great at scamming their customers.
The two always sold "rare breeds" which were not rare at all. Sekine even garnered the reputation of stealing back animals that he had sold so he can sell them again. He was even accused of poisoning a client's dog so that they would buy a new one. Eventually, this way of living put a target on their backs.
A client had realized their scamming ways and started pressuring the couple to refund the money. Instead of doing so, the couple decided to permanently get rid of the client in order to relieve the grief he was giving them. A similar scenario played out for three other victims.
The businessman disappeared after going home from work. His car was found at an underground parking lot a few weeks later. His family was quick to point the finger at Sekine, who the police already had an eye on for their scamming ways. The businessman went to get the money back from Sekine and Kazama when Sekine slipped poison into his drink. He was killed instantly.
They dismembered his body and disposed of it near Eikō Yamazaki's home. Yamazaki was an employee at the kennel. This is what they did with the other three victims as well. They tried their best to scatter the body parts.
Later, Yamazaki admitted that the crimes had taken place at his home under the command of Sekine. His testimony led police to uncover minor remains and belongings from the four victims. The couple was convicted based on the evidence and testimony of Yamazaki.
On March 21st, 2001, the couple was sentenced to death. Sekine died from a heart attack in 2017. Kazama is still awaiting her execution.