Yasuko Miyazawa

Status:

Open

Jurisdiction:

Tokyo Metropolitan Police (DEPARTMENT)

Offense Location:

Setagaya, Tokyo

Summary:

Yasuko Miyazawa, age 41, was stabbed to death on the night of December 30, 2000, transitioning into the early hours of December 31, along with her husband Mikio (44), daughter Niina (8), and son Rei (6). The unsolved murders occurred in the Kamisoshigaya neighborhood of Setagaya, Tokyo, Japan. The case remains unsolved.

Vital Statistics

Circumstances of Offense:

On the night of December 30, 2000, the last person to see anyone in the family alive was Yasuko's mother, who lived next door, when Niina came by to visit and watch TV. The last known activity definitively known to have been performed by a member of the family was when Mikio logged into a password-protected e-mail at 10:38pm. Sometime after 10:38pm, investigators believe that a man climbed to the second floor of the home, where he entered through the bathroom window. Forensic analysis indicates the six-year-old son, Rei Miyazawa, was first strangled silently in his second-floor bedroom while asleep, minimizing initial alarm. The father, 44-year-old Mikio Miyazawa, who had been working in a first-floor study, confronted the intruder upon hearing noise upstairs, leading to a violent struggle where Mikio sustained approximately 50 stab wounds from a sashimi knife. The assailant used one of the kitchen knives in the house to kill Yasuko and Niina after his sashimi knife broke as he was stabbing Mikio, leaving part of the blade in Mikio's head. Tokyo Metropolitan Police Department (TMPD) investigators concluded the family was killed between approximately 11:30 p.m. and 12:05 a.m. JST, and that the perpetrator likely entered through an open second-floor bathroom window near Soshigaya Park, possibly by climbing a fence and an air-conditioning unit. On the morning of December 31st, Yasuko's mother, Haruko, stopped by the Miyazawa house to check on her family after her phone calls to the house didn't go through. The bodies were discovered at approximately 10:40 a.m. on New Year's Eve. Yasuko's mother, Haruko, who lived next door, was the person who found them.

Additional Details:

Yasuko Miyazawa, the 41-year-old mother, was a kind and compassionate teacher who spent most of her time with their two children, eight-year-old Niina and six-year-old Rei. Yasuko was loved by her students and fellow teachers and known for her patience and caring nature. In the year 2000, Mikio Miyazawa (44), his wife Yasuko Miyazawa (41) and their two kids Niina (8) and Rei (6) lived in Soshigaya Park. They moved into the area in 1991 at which time it was a family housing complex with up to 200 units. The Miyazawa's house is located right next to a public park – specifically it pushes up against a children's play area: Choo Choo Train Park. The house is just above the number '23' to the left. The Metropolitan Government of Tokyo wanted to redevelop the land around Soshigaya Park so from 1991 onwards, neighbours started to sell up. By the night of the murders, there were only three other houses in that complex that were still inhabited. Police know so much about the killer — everything except who he is and why he committed such a violent crime. He left his DNA everywhere. He left clothes at the scene. He left the murder weapon. He used the victims' computer. He ate at least four ice creams from their freezer. And he stayed inside the house for hours as the family lay dead. We know he was still there past 1 a.m., as he used the family computer. It is widely believed that he also took a nap, ate melon, consumed four cups of ice cream, drank several bottles of barley tea and used the toilet. 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. It was reported that more than 100,000 yen in cash was stolen from the house. Almost 250,000 investigators have worked on this case, receiving more than 15,000 tip-offs from the public. 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. In addition to fingerprints and footprints, type A blood was collected from more than 10 places at the site of the crime. The killer's DNA turned out to be particularly unusual as he appeared to have European ancestry on his mother's side. Other DNA markers suggested a possible link to either China or Korea. Metropolitan Police Department estimates that he was born between 1965 and 1985 (15 to 35 years old at the time of the incident). The media attention and long investigation of the murders became a cause célèbre to abolish the statute of limitations for crimes that could merit the death penalty in Japan, which was removed in 2010. In 2019, the TMPD announced that the Miyazawa house would be torn down because of its age and risk of collapsing, with the interior already showing signs of deterioration.

Case Last Updated:

Jul 27, 2026