In order to avoid any concern over her abduction, the perpetrators forced Furuta to call her parents and tell them that she would be staying at a friend’s house for a while. The parents of the boy who owned the house were present at least part of the time Furuta was held captive, yet did not intervene, later claiming that they feared their son too much to do so.
The killers hid her corpse in a 55-gallon drum filled with concrete; the perpetrators disposed of the drum in a tract of reclaimed land in Kōtō, Tokyo. When the victim's mother was informed of what had happened, she fainted and had to be taken for psychiatric treatment.
The boys were arrested and tried as adults; but, because of Japanese handling of crimes committed by juveniles, their identities were concealed by the court. The magazine Shūkan Bunshun reported their real names, claiming that "human rights aren't needed for brutes".
For his participation in the crime, Kamisaku served eight years in a juvenile prison before he was released, in August 1999. In July 2004, he was arrested for assaulting an acquaintance, whom he believed to be luring a girlfriend away from him, and allegedly bragged about his earlier infamy. Kamisaku was sentenced to seven years in prison for the beating.
In July 1990, a lower court sentenced the leader to seventeen years in prison. The court sentenced one accomplice to a four- to a six-year term, one accomplice to a three- to a four-year term, and another accomplice to an indefinite five- to a ten-year term. The leader and the first two of the three appealed their rulings. The higher court gave more severe sentences to the three appealing parties. The presiding judge, Ryūji Yanase, said that the court did so because of the nature of the crime, the effect on the victim's family, and the effects of the crime on society. The leader received a twenty-year sentence, the second highest possible sentence of life imprisonment. Of the two appealing accomplices, the one that originally got four to six years received a five- to a nine-year term. The other accomplice had his sentence upgraded to a five- to a seven-year term.
Furuta's parents were dismayed by the sentences received by their daughter's killers and enjoined a civil suit against the parents of the boy in whose home the crimes were committed.