A 29-year-old Japanese man is on trial for allegedly stalking and killing his former girlfriend after spending months trying to track down where she lived — eventually disguising himself as a delivery worker to reach her home.
Takumi Ouchi appeared in court on Sept 14 and admitted killing 31-year-old Haruka Komatsumoto on Dec 31, 2025. Prosecutors say the attack came after he became obsessed with her following their breakup in 2024.
According to court testimony, Komatsumoto had blocked Ouchi’s phone number and social-media accounts after their relationship ended. He then spent about six months trying to discover her whereabouts, including using GPS tracking devices to follow her movements.
Komatsumoto, who worked as a nail artist, had contacted police anonymously on Dec 27, four days before her death, to seek advice about the situation. Police reportedly advised her to make a formal report after determining that there was no immediate emergency.
After locating her home, Ouchi arrived on Dec 31 wearing a disguise intended to make him appear to be a delivery worker. When Komatsumoto answered the door, prosecutors say he attacked her with a hammer before using a kitchen knife.
Ouchi told the court that he did not know his former girlfriend had remarried or was five months pregnant. He claimed that if he had known about her marriage and pregnancy, he did not think he would have carried out the attack.
Prosecutors have also pointed to his actions after the killing as evidence of a lack of remorse. According to court reporting, Ouchi visited a sex worker the day after the murder.
Police arrested him on Jan 21 after investigators identified surveillance footage placing him near Komatsumoto’s home around the time of the killing.
The case comes as Japan continues to examine how authorities can better protect people facing stalking threats. The government has been considering measures including GPS monitoring for people assessed as posing a high risk, following other recent cases in which stalking escalated into fatal violence.
Ouchi’s verdict is scheduled for Sept 30. Until the court reaches its decision, the allegations against him remain subject to the judicial process.
