In 2021, nurse Haruka Watanabe and her one-year-old daughter were found dead at their home in Niigata City. Initially considered a suicide or accident, investigation revealed horizontal rope marks inconsistent with hanging. Haruka's husband, Watanabe, admitted to killing them, motivated by his ongoing affair and financial debts. He had previously attempted to kill Haruka using sleeping pills and planned to use potassium chloride stolen from his hospital workplace. The trial began in 2024, resulting in a life imprisonment sentence, with an ongoing appeal. The case highlights infidelity, financial deception, and domestic violence leading to a double homicide.
Country: Japan
State/Province: Niigata, Japan
City/Region: Niigata City
Incident Type: Domestic Violence Homicide
Relationship Status: Married
Relationship Duration: Approximately 3 years
Incident Date: Nov. 7, 2021
Relationship Origins:
Relationship Stages:
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How the relationship or connection began.
Approximately 3 years
Important relationship phases recorded for this case.
Reported red flags or early concern points.
Contributing factors and possible motives from the available sources.
2021-11-07
Recorded relationship or case outcome.
English labels are shown first. Original-language titles are preserved for source verification.
事件解説チャンネル · Original language: Japanese
救急隊は「事故」と判断したのに…首に残る水平な痕と、看護師の夫が職場から盗み出した「10本の劇薬」【新潟市南区妻子事件】
Infidelity
The case involves a married couple where the husband engaged in a prolonged extramarital affair, leading to financial deception and escalating domestic conflict. The husband attempted multiple times to kill his wife, culminating in the murder of both wife and child to remove obstacles to continuing his affair. The pattern reflects infidelity-driven domestic violence with premeditation and deception.
Police investigation revealed horizontal rope marks inconsistent with hanging, leading to suspicion of homicide. Husband confessed and was arrested. Evidence included stolen potassium chloride, internet searches on killing methods, and fabricated suicide note. Trial began in 2024 with life imprisonment sentence; defense appealed. Investigation confirmed multiple prior attempts to kill the wife.
Initial emergency response treated the incident as suicide or accident. Confusion arose from the nature of neck marks and the staged suicide note. The husband's initial denial of financial theft complicated early investigation. The defense disputed intent regarding potassium chloride use.
The husband administered sleeping pills to impair the wife, causing a traffic accident. He stole potassium chloride intending to kill her but abandoned this plan. After prolonged affair and financial disputes, he strangled his wife and daughter with a rope purchased in advance, staging a suicide note. The motive was to eliminate obstacles to his affair and avoid divorce complications. The case was reconstructed from police interviews, digital evidence, medical records, and witness statements.
High risk due to ongoing infidelity, financial deception, prior attempted murders, and escalation to lethal violence. The offender's access to medical knowledge and substances increased lethality risk.
Early signs included financial irregularities, infidelity, and unexplained health issues. The offender's medical knowledge facilitated covert poisoning attempts. Horizontal neck marks and inconsistent death scene details are critical forensic clues. The case underscores the importance of investigating domestic conflicts and financial abuse as potential precursors to lethal violence.
Financial theft, wife's fainting and hospitalization, husband's affair, and wife's expressed intention to leave were key early signals.
Horizontal rope marks, husband's internet searches on killing methods, stolen potassium chloride, and fabricated suicide note helped connect the case.
Surveillance footage of bank withdrawals, medical records showing sleeping pill effects, digital messages, and husband's confession were strongest evidence types.
Neighbors described the family as polite and peaceful. Police officer witnessed and rescued wife after traffic accident. Wife's mother reported phone calls and messages indicating distress. Not reported any direct eyewitness to the murder.
Follow-up reports clarified husband's multiple attempts to kill wife, revealed affair details, and confirmed life imprisonment sentence with ongoing appeal.
Exact timing and full extent of husband's poisoning attempts remain partially unclear. Defense's claims about potassium chloride intent remain disputed.