Haruka Komatsumoto, a pregnant nail technician in Mito, Ibaraki Prefecture, was allegedly murdered by her ex-boyfriend Takumi Ouchi. The case involves stalking, obsessive behavior, and a brutal attack using two weapons—a hammer and a kitchen knife. Ouchi had a history of psychological instability, possessiveness, and dominance attempts in the relationship. He tracked Haruka's location using a GPS tag hidden in a stuffed animal sent to her family home. The murder was premeditated, with evidence of planning and rational actions to conceal the crime. Haruka had a history of domestic violence with a previous husband and had recently remarried. The prosecution seeks the death penalty due to the cruelty and social impact of killing a pregnant woman.
Country: Japan
State/Province: Ibaraki, Japan
City/Region: Mito
Incident Type: Murder
Relationship Status: Ex-partners
Relationship Duration:
Incident Date: Dec. 27, 2025
Relationship Origins:
Relationship Stages:
Contributing Factors:
Red Flags:
Motives:
Relationship Outcomes:
How the relationship or connection began.
Important relationship phases recorded for this case.
Reported red flags or early concern points.
Contributing factors and possible motives from the available sources.
2025-12-27
Recorded relationship or case outcome.
English labels are shown first. Original-language titles are preserved for source verification.
Eisuke_Himuro · Original language: Japanese
【水戸市妊婦ネイリスト◯人事件】後編 #水戸市ネイリスト#小松本遥 #大内拓実
Jealousy
The relationship between Haruka Komatsumoto and Takumi Ouchi was marked by obsessive jealousy and controlling behavior from Ouchi, who stalked and harassed Haruka after their breakup. The escalation from dating to separation was followed by stalking, surveillance, and ultimately a planned murder. The use of multiple weapons and premeditated tracking indicates a pattern of obsessive control and violent escalation.
Police arrested Takumi Ouchi based on evidence including GPS tracking, search histories on his smartphone indicating planning of murder and concealment, and physical evidence from the crime scene. Ouchi denies the charges but showed distress when confronted. The case is under trial with prosecution seeking the death penalty due to the cruelty and social impact of killing a pregnant woman.
No significant confusion reported; suspect identification is clear with strong evidence. Some uncertainty remains about exact timing and sequence of weapon use during the attack.
Ouchi met Haruka at a cabaret club where she worked to save money for her nail salon. They dated briefly but broke up due to Ouchi's controlling and condescending behavior. After the breakup, Ouchi stalked Haruka, using a GPS tag hidden in a stuffed animal to locate her. On December 27, 2025, Ouchi attacked Haruka at her apartment using a hammer to incapacitate her and then a kitchen knife to kill her. He placed a blood-stained bag on the living room table as a possible disguise. Ouchi disposed of the weapons near his family home. The police investigation uncovered digital evidence of planning and surveillance.
High risk due to stalking, obsessive behavior, prior domestic violence history, and evidence of premeditation including surveillance and weapon preparation.
Early signs of obsessive control and stalking after breakup are critical warning signals. Use of multiple weapons and surveillance devices indicate high planning and intent. Third parties should avoid sharing victim location information to prevent enabling stalkers. The case highlights the dangers of unresolved relationship conflicts escalating to lethal violence.
Persistent stalking, harassment, and obsessive attempts to contact the victim after breakup; use of GPS tracking device; blocking and rejection by victim.
GPS tag in stuffed animal, suspicious internet searches about murder and evidence concealment, surveillance of victim's social media and contacts, physical evidence of multiple weapon use.
Digital evidence from smartphone, GPS tracking data, autopsy showing multiple hammer blows and defensive wounds, witness testimonies about stalking and harassment.
Neighbors and acquaintances described Haruka as bright and responsible; colleagues and friends noted Ouchi's controlling behavior and obsession; mutual acquaintances refused to disclose victim's location despite Ouchi's inquiries; police received victim's harassment report.
No follow-up reports available beyond initial investigation and trial preparations.
Exact reasons for breakup remain known only to parties; precise sequence of weapon use during attack is inferred but not fully confirmed.