Kyoko comes from a family of famous detectives. Her father, Jin Kirigiri, wasn't interested in being a detective, and he was kicked out of the family by his father Fuhito Kirigiri before Kyoko was even born.
Some time afterward, Jin married a woman from Uzuchi family and they had Kyoko. It appears that when she was very young, she and her father spent some time with Jin's close friend Koichi Kizakura. After learning about her existence, Fuhito invited Jin back to the family solely because he wanted to make the girl his heir. He began strict training to make Kyoko a true detective, though Jin still very much disliked his father. When Kyoko was only 7 years old, her mother turned ill and was hospitalized when Kyoko and Fuhito were doing detective work abroad. Jin tried to contact them, but Fuhito refused to aid his family and didn't even let Kyoko see her dying mother, because to Fuhito being a detective was more important than anything else. Kyoko's mother then died, with Kyoko's last memories of her being "a white face floating above a hospital bed". Absolutely furious with his father, Jin left the family, and Fuhito encouraged Kyoko to hate him by claiming that Jin only used her mother's death as an excuse to leave the family and pursue his own dreams.
Kyoko became very close to her grandfather, Fuhito, who raised her and taught her all she currently knows in the detective business, and he protected her from anything he deemed a threat. However, Fuhito was also shown to be extremely strict in his wish to make Kyoko a perfect heir and a detective, even causing the young girl some emotional issues as Fuhito wanted her to be a detective above everything else.
