Setagaya family murder

From Wikipedia, the free encyclopedia
Jump to navigation Jump to search
Setagaya family murder
A white, two-story house surrounded by trees with a large, empty field of grass in the foreground
The Miyazawa home in Setagaya in 2010. Neighboring houses at the time of the murders have since been demolished.
LocationSetagaya, Tokyo, Japan
DateDecember 30, 2000 (2000-12-30)
TargetMiyazawa family
Attack type
Mass murder, home invasion
  • Mikio Miyazawa, 44
  • Yasuko Miyazawa, 41
  • Niina Miyazawa, 8
  • Rei Miyazawa, 6

The Setagaya family murder (世田谷一家殺害事件, Setagaya ikka satsugai jiken) refers to the unsolved murders of the Miyazawa family in Setagaya ward of Tokyo, Japan, on 30 December 2000.

Mikio Miyazawa, Yasuko Miyazawa, Niina Miyazawa, and Rei Miyazawa were murdered during a home invasion at night by an unknown assailant who then remained in the Miyazawas' house for several hours before disappearing. Japanese police launched a massive investigation that uncovered the killer's DNA and many specific clues about their identity, but the perpetrator has never been identified. The media frenzy and long investigation of the Setagaya murders became a cause célèbre to abolish statute of limitations in Japan, which was removed in 2010.[1]


The rear of the Miyazawa house from Soshigaya Park in 2010.

On 31 December 2000, the corpses of 44-year-old Mikio Miyazawa, his 41-year-old wife Yasuko, and their children, 8-year-old Niina and 6-year-old Rei, were discovered by Yasuko's mother, Asahi Geino, at their house in the Kamisoshigaya neighborhood of Setagaya, in the western suburbs of Tokyo.[2] Mikio, Yasuko, and Niina had been stabbed to death while Rei had been strangled.[3] Investigation of the crime scene by the Tokyo Metropolitan Police Department concluded that the family had been murdered on December 30 at around 11:30 p.m. (Japan Standard Time), after which the killer stayed in the house for several hours.[4]

The Miyazawa's killer entered through the open window of the second floor bathroom at the rear of the house, located immediately adjacent to Soshigaya Park, and gained access by climbing up a tree and then removing the window screen. The killer used his bare hands to strangle Rei, sleeping in his room on the second floor, killing him through asphyxiation. Mikio rushed up the first floor stairs after he detected the disturbance in Rei's room, fighting and injuring the killer until being stabbed in the head with a Sashimi bōchō knife. A police report claimed that part of the Sashimi knife's blade broke off inside Mikio's head, and the killer then attacked Yasuko and Niina with the broken knife until using a Santoku knife from the Miyazawa's house to murder them.

The killer remained inside the Miyazawa house for 2 to 10 hours, using the family computer, consuming barley tea, melon, and ice cream from their refrigerator, using their toilet, treating his injuries using first aid kits and other sanitary products, and taking a nap on a sofa in the second floor living room. An analysis of Mikio Miyazawa's computer revealed that it had connected to the internet the morning after the murders at 1:18 a.m. and again at around 10 a.m., around the time Yasuko's mother Asahi entered the house and discovered the murders. Asahi became suspicious after being unable to call her daughter (the killer had unplugged the phone line) and visited the house but received no answer after ringing the doorbell. Authorities believe the killer had stayed in the house until at least 1:18 a.m. but the computer usage at 10 a.m. could have also been accidentally triggered by Asahi during her discovery of the crime scene.[4]


Police have been able to deduce several very specific clues to the perpetrator's identity, but have been unable to produce or apprehend a suspect. It was determined that the killer had eaten string beans and sesame seeds the previous day after analyzing feces from the killer in the Miyazawas' bathroom.[2] They determined that the clothes and Sashimi knife left behind by the killer had been purchased in Kanagawa Prefecture. Police also learned that only 130 units of the killer's sweater were made and sold, but they have only been able to track down twelve of the people who bought the sweaters.[3]

The investigation into the murders is among the largest in Japanese history, involving over 246,044 investigators who have collected over 12,545 pieces of evidence.[5] As of 2015, forty officers were still assigned to the case full-time.[3] Every year, the Tokyo Metropolitan Police Department makes an annual pilgrimage to the house for memorial ceremonies.[6][7] The Seijo Police Station is designated to investigate the case.[8]

The Tokyo Metropolitan Police Department is currently offering a 20 million yen reward to any person who can help officers to find clues that lead to a suspect and/or close the case.[9]


Tokyo police found the killer's DNA and fingerprints in the Miyazawas' house, but none matched the databases of the Tokyo police, indicating that they do not have a criminal record. The killer's blood was gained during an analysis of the murder scene that revealed traces of Type A blood, which would not have belonged to the Miyazawa family. A DNA analysis of the Type A blood determined the killer is male and possibly mixed-race, with maternal DNA indicating a mother of European descent, possibly from a South European country near the Mediterranean or Adriatic Sea, and paternal DNA indicating a father of East Asian descent. It is considered possible that the European maternal DNA comes from a distant ancestor from the mother's line rather than a fully European mother. Analysis of the Y-chromosome showed the Haplogroup O-M122, a common haplogroup distributed in East Asian peoples, appearing in 1 in 4 or 5 Koreans, 1 in 10 Chinese, and 1 in 13 Japanese. These results led to Tokyo Metropolitan Police to seek assistance through the International Criminal Police Organization as the killer may not be Japanese or present in Japan.

Physically, the killer is believed to be around 170 centimeters tall and of thin build.[6] The police estimate the killer was born between 1965 and 1985 (15 to 35 years-old at the time of the incident) due to the physicality required for entering the Miyazawa house and committing the murders. The Miyazawas' wounds indicate that the killer is likely to be right-handed.


In 2015, An Irie, older sister of Yasuko Miyazawa, filed a complaint to the Broadcast and Human Rights and Other Related Rights Committee of the Broadcasting Ethics & Program Improvement Organization after she claimed that the TV Asahi documentary aired in 2014 misrepresented her after a TV Asahi reporter and ex-FBI agent used profiling to back a theory that the killer murdered the Miyazawas out of resentment.[10]


  1. ^
  2. ^ a b "New book claims to shed light on Setagaya family murders in 2000". Japan Today. December 13, 2015. Retrieved June 19, 2016.
  3. ^ a b c "Setagaya family murders remain unsolved 15 years later". Japan Today. December 31, 2015. Archived from the original on July 26, 2016. Retrieved June 19, 2016.
  4. ^ a b "Family's killer may have left home at night". The Daily Yomiuri. December 13, 2014. Retrieved June 14, 2019 – via Questia.
  5. ^ "Police vow to solve 2000 murder of Tokyo family". The Mainichi. December 31, 2015. Retrieved June 19, 2016.
  6. ^ a b "Setagaya family murders remain unsolved 17 years later". Japan Today. December 30, 2017. Archived from the original on May 23, 2018. Retrieved June 13, 2019.
  7. ^ "MPD pledges to solve 2000 murder of Tokyo family of 4". The Mainichi. December 31, 2017. Retrieved June 13, 2019.
  8. ^ "Criminal cases with a cash reward for information(懸賞広告事件)". Tokyo Metropolitan Police Department. December 16, 2018. Retrieved June 13, 2019.
  9. ^
  10. ^

External links[edit]