Disappearance of Mayumi Arashi

In 1994, a 27-year-old housewife named Mayumi Arashi vanished after leaving her family home in Tokyo, leaving behind her 1-year-old daughter. She said she was going to meet her schoolmate. Her older sister, Yoko, later checked with this classmate, who said no such meeting was planned. Her whole family started searching for her but to no avail. Later that day, a memo is found inside Yoko's wardrobe, which reads "I was going out with A, but was betrayed" and "I'm sorry". At the bottom of the memo is A's phone number. Yoko contacts A, who tells her that "I met with Mayumi earlier that day" and "want to be in jail if Mayumi ever turns up dead".

A day later when police tailed "A", they found him entering forest holding two drinks. The police then lost track of him and found no trace of Mayumi. Fast forward to 2011, during an interview about Mayumi’s disappearance, Yoko is interviewed and she tearfully recounted the events above. Her father was then interviewed at a different location and stated that they knew nothing about Mayumi's alleged affair until they found that memo, and on the day she disappeared, it seemed like something was bothering her. But what caught the attention of viewers at home, and ignited speculation across the Japanese internet boards was a piece of paper stuck to a shelf behind the father, which went completely unremarked. On the piece of paper were the words "Don't believe what Yoko says".