← Back to Japan casesShizuka Yamada Allegedly Murdered by Makoto Nasu, Setagaya, Tokyo, Japan
Case Summary
On December 28, 2006, 22-year-old Shizuka Yamada was found dead in her apartment in Ohara, Setagaya Ward, Tokyo. Police treated the death as murder after finding apparent strangulation marks. Her coworker Makoto Nasu was arrested after investigators linked him to the apartment key and Shizuka's card case. The source reports that Nasu had persistently pursued Shizuka after she rejected his invitation, stole and copied keys to access her apartment, attacked her after she returned from work, and later attempted to destroy evidence by setting the apartment on fire. He was convicted and received a life sentence, which became final after he did not appeal.
Basic Information
Country: Japan
State/Province: Tokyo, Japan
City/Region: Setagaya
Incident Type: Murder
Relationship Status: One-sided love
Relationship Duration:
Incident Date: Dec. 28, 2006
Relationship Journey
Relationship Origins:
- Met at Workplace
- Friends circle
Relationship Stages:
- No data available.
Analysis
Contributing Factors:
- No data available.
Red Flags:
- Meeting people privately / hiddenly
- Deception after incident
- Escalation Pattern / Violence
- Suspects identified
- Threats
- Stalking / Repeated Harassment
Motives:
- Control/domination
- Desire for new relationship
Relationship Outcomes:
- Arrest made
- Deadbody recovery
Source Video
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People Link Graph
Shizuka Yamada Allegedly Murdered by Makoto Nasu, Setagaya, Tokyo, Japan
Relationship Journey Graph
Origin
- Met at Workplace
- Friends circle
How the relationship or connection began.
Status
- One-sided love
Stages
Important relationship phases recorded for this case.
Warning Signals
- Meeting people privately / hiddenly
- Deception after incident
- Escalation Pattern / Violence
- Suspects identified
- Threats
- Stalking / Repeated Harassment
Reported red flags or early concern points.
Pressure Points
- Control/domination
- Desire for new relationship
Contributing factors and possible motives from the available sources.
Incident
2006-12-28
Outcome
- Arrest made
- Deadbody recovery
Recorded relationship or case outcome.
AI Intelligence Assessment
Relationship Pattern
Romantic Obsession and Stalking
Pattern Analysis
The source describes a one-sided workplace pursuit rather than a mutual romantic relationship. Nasu reportedly continued contacting Shizuka after she declined his invitation, aligned his work shifts with hers, monitored her residence, and obtained unauthorized access to her apartment. The reported progression moved from unwanted communication and surveillance to planned intrusion, sexual violence, homicide, threats, and attempted evidence destruction.
Investigative Notes
The victim's older sister found her body after becoming concerned that the victim's phone was switched off. Police established a task force at Kitazawa Police Station and estimated the death around noon on December 28, 2006. Investigators found apparent strangulation marks, a disturbed room, and valuables left behind, suggesting that the scene was not a straightforward robbery. Coworkers identified Makoto Nasu, who reportedly lacked an alibi. A key to the apartment and the victim's card case were recovered from his home. The source reports that Nasu admitted the offense, was arrested, prosecuted for murder and arson-related conduct, and received a life sentence. The sentence became final after he did not appeal.
Investigation Confusion
The investigation initially faced uncertainty because the apartment was locked, the victim was not known to have a boyfriend, and the room appeared to have been searched. Investigators considered whether the killing involved a lover, family member, or robbery, while the source later connected the locked door to Nasu's copied key. At trial, Nasu denied having murderous intent, but the prosecution argued that repeated strangulation supported intent to kill. The source also describes an attempted arson plan that failed after the victim's sister arrived.
Case Reconstruction / Puzzle Pieces
Shizuka met Nasu through their shared workplace in October 2006. After she declined his invitation and reportedly did not respond to his repeated emails, Nasu continued pursuing her and arranged matching shifts. He allegedly stole coworkers' keys, copied them, and tested them against Shizuka's apartment until one worked. On December 28, after Shizuka returned from an overnight shift, Nasu allegedly entered with a copied key, waited for her, used wine and sleeping pills in an effort to incapacitate her, and attacked her when she resisted. The source reports repeated strangulation, Nasu's departure with the apartment locked, his return to prepare an arson, and his flight when Shizuka's sister arrived. Police later linked him to the scene through his lack of an alibi, recovered property, and his reported admission.
Risk Assessment
The reported combination of repeated unwanted contact, inability to accept rejection, workplace access, surveillance, unauthorized key duplication, planned intrusion, coercive violence, and post-incident threats represents a severe escalation pattern. The source does not provide a broader history of violence or a professional behavioral assessment, so risk conclusions are limited to the reported conduct.
Key Takeaways
The case illustrates how a rejected or one-sided workplace pursuit can escalate when repeated contact, surveillance, unauthorized access, and entitlement are not interrupted. The reported warning signs included 60 unwanted emails, shift manipulation, residence surveillance, key theft and copying, a planned nighttime intrusion, and threats after the homicide. The source is useful for pattern comparison but presents some behavioral interpretations as narration rather than documented clinical findings.
AI Case Q&A
What early signals mattered most?
The most significant reported early signals were Nasu's repeated unwanted emails, his continued attempts to contact Shizuka after rejection, his efforts to arrange matching shifts, and his inability to accept her lack of interest. The later key theft, apartment surveillance, and copied-key testing marked a substantial escalation.
Which clues helped connect the case?
The locked apartment, the absence of a clear robbery motive, Nasu's lack of an alibi, coworker information about his pursuit of Shizuka, and the recovery of her apartment key and card case from his home helped connect him to the case.
Which evidence types appeared strongest?
The source describes physical evidence including the copied apartment key, the victim's card case and cash card, the apparent strangulation marks, and the disturbed apartment. It also reports coworker accounts, the estimated timeline, Nasu's lack of an alibi, his reported admission, and prosecution evidence concerning repeated strangulation.
Witness / Eyewitness Statements
The victim's older sister reportedly said she had not heard that Shizuka had a boyfriend and found the victim after discovering that her phone was switched off. Coworkers reportedly described Nasu as proud and immature and told investigators about his conduct toward Shizuka. The store manager described Shizuka as well liked. No independent eyewitness to the assault was reported.
How did follow-up reports change the understanding?
Follow-up investigation changed the understanding from a mysterious locked-room killing with possible robbery features to a case involving a coworker who had persistently pursued the victim. The later account identified copied keys, a planned sexual assault, repeated strangulation, attempted arson, and post-incident threats. Court proceedings further disputed Nasu's claim that he lacked intent to kill.
What remained unclear?
The source does not provide the older sister's name, a complete forensic account, or an independently reported explanation of every item found disturbed in the apartment. It also does not establish a mutual romantic relationship; the relationship was described as one-sided. Some psychological conclusions about Nasu's personality and lack of remorse are narrative interpretations rather than clinical findings.