On the morning of December 31, 2000, a grandmother let herself into her daughter's house in Setagaya, Tokyo, after nobody answered the door. Inside, she found her daughter Yasuko, son in law Mikio, and their two children, eight year old Niina and six year old Rei, all killed sometime the night before. It remains one of the most heavily investigated unsolved murders in Japanese history. Investigators believe the killer climbed a fence, used an air conditioning unit to reach a second floor bathroom window, and entered the house that way. Six year old Rei was killed first, in his sleep. Police believe Mikio may have heard something and gone to check, and was killed trying to stop what was happening. Yasuko and Niina were killed shortly after. What happened next is what makes this case so unusual. The killer didn't leave. He stayed inside the house for hours, eating food from the refrigerator, drinking their tea, using their computer, treating an injury with their first aid kit, and using the bathroom without flushing. He went through drawers and papers, took some cash but left more behind, and eventually left through the house, abandoning his knife, his jacket, gloves, a hat, and other belongings on his way out. Investigators recovered an enormous amount of physical evidence, DNA, fingerprints, fibers, even sand found in a bag he left behind, later traced to a very specific region of the Nevada desert. They determined he'd eaten string beans and sesame seeds the day before, based on analysis of what he left in the bathroom. They traced his shirt to a batch of only 130 ever sold, and tracked down twelve of the buyers. His shoes were made in South Korea. His DNA suggested he was male, likely right handed, and of mixed ancestry, with maternal DNA pointing toward Southern Europe and paternal DNA pointing toward East Asia. None of it matched anyone in their databases. Over the following two decades, more than 246,000 investigators have worked the case in some capacity, collecting over 12,500 pieces of evidence. Police have repeatedly revised their estimate of the killer's age, at different points believing he could have been as young as 15 or well into his 30s at the time. In 2021, new technology let them visually identify someone who'd purchased the same model of knife used in the murders, but his DNA didn't match, and he was ruled out. if you're reading this whole story, comment your country name with flag, so we all know our "all reader" gang. do follow as well:) The case became so notorious that public pressure over it contributed to Japan abolishing its statute of limitations on crimes punishable by death in 2010. Every year, police still make a pilgrimage to the site for a memorial. A reward of 20 million yen remains active for information leading to an arrest. The family's house sat empty for years afterward, preserved as evidence, until police announced plans to tear it down due to age and safety concerns, a decision the family and supporters publicly appealed. In 2026, two unrelated men were arrested after breaking into the long vacant house to steal from it, telling police they hadn't known its history. No one has ever been arrested for the murders themselves. No suspect has ever been named. Every physical trace the killer left behind, food he ate, tea he drank, sand in his bag, a shirt from a batch of 130, has been preserved and studied for over two decades, and still hasn't led to a single arrest. How does someone leave this much of themselves behind, DNA, fingerprints, his own blood, and still never get identified after 25 years. Why would a person kill an entire family and then stay in their house for hours afterward, eating their food and sleeping on their couch, instead of leaving immediately? #tracethetruth #crimestorytime #truecrime #truecrimestory #reader #readersoftiktok #readers #mystery - @trace.the.truth