Takumi Ouchi, a 28-year-old Japanese man, couldn’t move past a romantic breakup and resorted to using a tracking gadget to monitor his ex-girlfriend, as reported by the South China Morning Post. Komatsumoto was the victim of Ouchi’s actions.
Ouchi and Komatsumoto’s relationship lasted under a year, concluding with their separation in 2024. Subsequently, he persistently attempted to make contact, leading her to block all means of communication. The final straw for Ouchi came upon learning of Komatsumoto’s marriage and pregnancy. It was then that his plan for revenge materialized. He dispatched a package to the woman’s parents containing a plush toy. The accompanying note falsely claimed the item was a lottery prize won at a popular amusement park.
Ouchi had secretly embedded a miniature GPS tracker within the gift. Neither the parents nor Komatsumoto herself, despite taking the toy to her new residence, suspected anything amiss. The device instantaneously began broadcasting the woman’s precise whereabouts in real-time, thus exposing her address, which she was likely safeguarding. Having acquired this intelligence, the perpetrator waited for an opportune moment. That moment arrived on December 31, 2025, while Komatsumoto’s husband was away from home. After breaking into the apartment, Ouchi executed a brutal assault: he beat the woman and inflicted multiple stab wounds. Investigators later observed that the nature of the injuries on the victim’s arms clearly indicated her desperate attempts to shield her unborn child.
Despite Ouchi’s efforts to deny involvement following his apprehension, incontrovertible evidence—CCTV footage—damages his claims. Komatsumoto’s murder deeply shook Japanese society and refocusing law enforcement’s attention on the growing issue of technological stalking. Statistics from the Japanese National Police reveal a worrying trend: while only three incidents involving the use of GPS devices for stalking were recorded in 2021, this figure surged to 196 by 2023, further increasing to 370 in 2024, and reaching an alarming 592 in 2025.
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