The Fukuoka Family Massacre

Almost all of us have a routine that we follow, whether consciously or subconsciously. When we are living with our families, our family time is spent having dinner together or maybe watching television. The Fukuoka Family was one such family of four, who lived together in a house in Japan. They might be happy, living their lives without worries until one dreadful night when rather than expecting one member to enter the house, three more did, and decided to end the lives of all by murdering them one by one. What was supposed to be a night which filled their bank accounts, resulting in four murders and a case so rare, that it resulted in a clash between two countries?