Kamisoshigaya District and the Setagaya Family Murder Case

Background and Context

Location: Kamisoshigaya, Tokyo, Japan.
Year: 2000 marked significant changes, including gentrification and urban expansion.
Family: The Setagaya family consisted of Mikio (44), Yasuko (41), Niina (8), and Rei (6).
Living Situation: One of four families remaining in a once-bustling neighborhood.
Plans to Move: The family planned to move due to urbanization but delayed due to concerns for their children's adjustment, especially for Rei, who had a developmental disorder.

Day Activities: Family did New Year's shopping and spent the evening together before going to bed.
Entry: The perpetrator entered the home through the second-floor bathroom window, likely using a fence or tree.

Rei (6): Strangled in his sleep.
Mikio (Father): Stabbed with a sashimi knife, ultimately found at the staircase base with multiple wounds.
Yasuko and Niina (Mother & Daughter): Attacked in the attic and tried to escape; both were killed with severe brutality.

Stayed for 2+ hours: Ate ice cream and barley tea, used first aid, sorted through documents, and left behind clothing and evidence.
Computer Use: Accessed the family computer at 1:18 am, creating a folder.
Left evidence: Including fingerprints, DNA samples, and unflushed toilet waste.

Physical Evidence: Fingerprints, DNA, clothing, shoeprints, and sand in a hip bag.
Challenges: Despite evidence, no match in Japan or in collaboration with Korean authorities.
DNA Analysis: Mixed ancestry, likely Southern European mother and East Asian father.

Burglary Gone Wrong: Unlikely due to the sequence and nature of the murders.
Serial Killer: Based on brutality and lack of remorse.
Revenge or Grudge: No evident motive; the skater dispute theory was weak.
Military Connection: Theory based on sand analysis from near a US Air Base.
South Korean Hitman: Theory involving a hired killer by land developers.
Teenage Perpetrator Theory: Based on an online post but lacks substantial evidence.

Unsolved Case: Despite extensive investigation and evidence.
Statute of Limitations: Abolished for murder in Japan in 2010.
Reward Offered: 20 million yen for information leading to an arrest.
Public and Family Impact: Family member continues to seek justice; case remains a significant cultural reference in Japan.
Ongoing Investigation: Largest in Japanese history with no resolution yet.