Gen Sekine (January 2, 1942 – March 27, 2017) was a Japanese dog breeder and serial killer who, together with his common-law wife Hiroko Kazama, murdered at least four clients in Kumagaya from April to August 1993 in what were called the Saitama Dog Lover Murders (Japanese: 埼玉愛犬家連続殺人事件). Both were sentenced to death for their crimes, but Sekine died on death row prior to execution.