|Real World Bio|
|Name||Unrevealed (possibly Shinichirou Azuma)|
|Alias|| Seito Sakakibara|
|Pathology|| Unclassified Killer|
|No. of Victims|| 2 killed|
"This is the beginning of the game... You police guys [sic] stop me if you can... I desperately want to see people die, it is a thrill for me to commit murder. A bloody judgment is needed for my years of great bitterness."
"Seito Sakakibara", also referred to as "Onibara" or "Boy A", is a killer who used the symbol of The Zodiac Killer as his signature. To this day, his real name remains hidden due to the seriousness of the crimes and the fact that the perpetrator was a minor at the time.
Not much about Seito's life prior to the murders has been disclosed, other than he committed many acts of animal cruelty by age 12 and also began bringing cutting weapons to school, commenting that carrying them around helps "ease his irritation". Starting sometime on February, Seito assaulted three schoolgirls within a two-month span. On March 16, he escalated to murder, killing 10-year-old Ayaka Yamashita. Two months later, on May 24, he abducted a special-education student, 11-year-old Jun Hase, and murdered him, decapitating and mutilating him using a hand saw. He then discarded Hase's head, along with a letter for the authorities, back at the school. It was found three days later by a school janitor. When local police read the letter, they found that Seito left a signature at the end of the letter, a cross-like symbol reminiscent of the one utilized by the infamous Zodiac Killer.
On June 6, Seito sent another letter to the police, in which he confessed to murdering Jun Hase, threatened that there would be more murders to follow, and naming himself as "Sakakibara Seito". There was a local media panic, and as a result, his name was misreported as "Onibara". Enraged, Seito sent yet another letter declaring that he will kill three "vegetables" per week should there be another misconception of the name. On June 28, police were able to apprehend Seito as a suspect for Jun Hase's murder; Seito also confessed to the murder of Ayaka Yamashita and the assaults of the three other schoolgirls. Exactly how police were able to pin Jun Hase's murder on Seito remains unknown. Seito has then been charged for his crimes and sent to juvenile detention. On March 11 of 2004, it has been announced that Seito, now aged 21, has been released on a provisional basis, then will be fully released on January 1 of the following year. The announcement was met with criticism, with many stating that due to the unusually sudden revelation, Seito shouldn't be released and sent to a prison instead. The release went on exactly as planned, however.
Three years after Seito's June 28, 1997 arrest and conviction, the Diet of Japan lowered the legal age of criminal responsibility for 16 years old to 14 years old. Following the June 1, 2004 murder of Satomi Mitarai, which was committed by an 11-year-old girl whose name was revealed only as "Girl A", discussions for further revision to the law have been initiated. There has also been a number of people who have stated that Seito was wrongfully accused. Among them were Shōjirō Gotō, a lawyer specializing in false-accusation cases; Hidehiko Kumagai; and Nobuyoshi Iwata, Seito's former principal.
Seito's method of killing his victims were varied. When he killed Ayaka Yamashita, he bludgeoned her to death with a steel pipe. Seito murdered Jun Hase with a hand saw, using it to decapitate and mutilate him.
- February-March: Three unnamed girls (alleged; all non-fatally assaulted within a two-month span)
- March 16: Ayaka Yamashita, 10 (bludgeoned with a steel pipe)
- May 24: Jun Hase, 11 (decapitated and mutilated with a hand saw)