The brutal and callous murder of a high school girl in 1989 by four teenage boys shocked an entire nation to its core. The extreme cruelty and depravity of the perpetrators towards their victim also ensured it would become one of the world most notorious crimes.

The horrifying story begins on a chilly November's day in the Japanese city of Misato. 16-year-old Furuta Junko was cycling home from her part-time job, when she was kidnapped by Hiroshi Miyano, J Ogura, Shinji Minato, and Yasushi Watanabe. They would hold her captive for over 40 days in a house in the Ayase district of Tokyo, subjecting her to a daily routine of sadistic and sickening torture.

Furuta was raped, beaten and sodomised multiple time a day by the gang and their friends - some of whom were members of yakuza organised crime groups.

Her abductors lit fireworks in her vagina and anus, which caused severe burns, tearing and bleeding. She was starved and forced to eat cockroaches, as well as drink her own urine.

At times, she was suspended from the ceiling of her room and used as a punching bag by her captors. These pitiless beatings damaged her organs and caused internal bleeding, making her writhe in agony.

Yet there was even worse to come, as the savagery and inhumanity of her abductors appeared to know no limits.

The four boys poured hot wax on her eyelids, stuck sawing needles in her breasts, and even ripped off her left nipple with pliers. They dropped iron barbells on her torso, making her lose the control of her bladder and bowels.

She would eventually die from her injuries on January 4, 1989, having endured over a month of incomprehensible barbarity. Her killers tried to conceal her body in a drum filled with over 50 gallons of cement.

However, two of the gang were picked up by police later in January in connection with the kidnapping and assault of a 19-year-old woman they accosted in December.

Under police questioning, they accidentally confessed to Furuta's kidnapping and gave the location of her body, which they found the following day.

Police eventually arrested the remaining two members of the gang in April. The perpetrators were charged with a range of crimes, including abduction, rape, and murder.

The court sentenced Miyano, the ringleader, to 20 years in prison. Ogura received eight years in juvenile prison, while Minato and Watanabe received five to seven years and five to nine years, respectively.

The lenient sentences caused outrage, with many demanding the death penalty for the convicted gang.

Furuta's mother reportedly had a mental breakdown after hearing the graphic details of her daughter's ordeal and spent time on a psychiatric ward for treatment.