On November 25, 1988, four boys, including a 17-year-old whose personal name was Jō and would be later given the surname Kamisaku, abducted and held Furuta, a third-year high school (12th grade) student from Misato, Saitama Prefecture, for 44 days. They kept her captive in the house owned by the parents of Kamisaku, in the Ayase district of Adachi, Tokyo.
To forestall a manhunt, one of them forced Furuta into calling her own parents and telling them that she had run away from home, but was with “a friend” and was not in danger. He also browbeat her into posing as the girlfriend of one of the boys when his (Kamisaku’s) parents were around, but when he was sure they would not call the police, he dropped the pretext. Furuta tried to escape several times, begging the parents to help her, but they did nothing, apparently out of fear that a second boy would hurt them. This second boy was at the time a low-level Yakuza leader and had bragged that he could use his connections to kill anyone who interfered.
According to their statements at their trial, the four of them raped her (over 400 times), beat her with metal rods and golf clubs, introduced foreign objects including a hot light bulb into her vagina, made her eat cockroaches and drink her own urine, inserted fireworks into her anus and set them off, forced Furuta to masturbate, cut her nipple with pliers, dropped dumbbells onto her stomach, and burned her with cigarettes and lighters. One of the burnings was punishment for attempting to call the police. It was also stated that some time after the first acts of torture, she became unable to drink water, which would cause her to vomit whenever she attempted to do so. At one point her injuries were so severe that according to one of the boys it took more than an hour for her to crawl downstairs to use the bathroom. They also related that “possibly a hundred different people” knew that Furuta had been imprisoned there, but it is not clear if this means they visited the house at different times while she was imprisoned there, or themselves either raped or abused her. When the boys refused to let her leave, she begged them on several occasions to “kill (her) and get it over with.”
On January 4, 1989, using a loss at mahjong solitaire as a pretext, the four beat her with an iron barbell, poured lighter fluid on her legs, arms, face and stomach, and set her on fire. She died later that day of shock. The four boys claimed that they were not aware of how badly injured she was, and that they believed she had been malingering.
On January 5, the killers hid her corpse in a 55-gallon drum filled with concrete; the perpetrators disposed the drum in a tract of reclaimed land in Kōtō, Tokyo.