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Proof of Death: When the Killer Answered Back
Police Doubted the Bones Until the Killer Sent Her Photograph: The Serial Murders of Mari Kono
A box arrived at a Saitama family's doorstep containing ten baby teeth, underwear, and sandals-the remains of their missing four-year-old daughter. When investigators publicly questioned whether the bones were authentic, the killer responded with something no detective expected: a photograph of the corpse, signed with a false name but bearing traceable handwriting. What followed was a cascade of communications that revealed a predator operating in plain sight, following funerals in real time and taunting authorities with knowledge only the killer could possess.
In this episode, we trace the 1988-1989 Saitama serial killings through the lens of a criminal investigation transformed by direct communication between perpetrator and family. We examine the contradictions embedded in the case: the handwriting evidence that arrived through the killer's own need for recognition, the escalation between the third and fourth murders that changed everything, and the psychiatric evaluation that concluded a man with severe dissociative traits was nonetheless fully criminally responsible. How does a brilliant child become invisible to the world, and what does it mean when that invisibility is finally broken through violence?
Victim: Mari Kono
Date: August 22, 1988 - July 23, 1989
Location: Saitama Prefecture, Japan
Status: Serial killer arrested and convicted
- Four girls aged four to seven disappeared over eleven months; the killer had no criminal record and lived with his parents
- The first three murders followed a pattern of escape; the fourth victim was retained at the killer's home, filmed, and partially cannibalized
- Miyazaki sent a package to the victim's family after police publicly doubted authenticity, then escalated to sending a photograph and attending the funeral while writing letters describing decomposition
- The killer's apartment contained over five thousand films, hundreds of mangas including extreme horror series, and his own recordings documenting the crimes
Mari Kono, Saitama Prefecture serial murders 1988, Tsutomu Miyazaki, child abduction, serial killer, Japan true crime, unsolved psychology, forensic investigation, criminal investigation, homicide, true crime English
To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com.
© 2026 OBOMEDIA. All rights reserved.
This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].
To listen ad-free and access premium episodes, start your 30-day free trial at obomedia.com
OBOMEDIA presents true crime storiesa true crime podcast built on real cases.
Every true crime story in our crime files follows the crime investigation from the missing person report to the trial: investigators and police building a murder case, a police investigation gone cold, justice for the victim and those who survived.
We open the unsolved murder, the cold case reopened decades later, the mysterious death, the disappearance, the serial killer, the family murder, the murder mystery; the missing persons a missing woman, a missing girl, a missing man found dead and the missing and murdered.
From the infamous case to the unsolved case, from classic true crime to dark true crime and disturbing true crime: true crime reports, real crime stories, real murder cases, true murder stories and unsolved mysteries one true crime case at a time, from the OBOMEDIA true crime vault.
© 2026 Created with OBOMEDIA technology. All rights reserved. This episode and its content (audio, text and related materials) are the property of their respective creator and are distributed under the OBOMEDIA name on platforms such as Apple Podcasts, Spotify, Amazon Music and Pocket Casts. Reproduction, distribution, editing or commercial use, in whole or in part, without prior written permission is prohibited. For permissions, licensing and business inquirie
A box arrived at a Saitama family's doorstep containing ten baby teeth, underwear, and sandals-the remains of their missing four-year-old daughter. When investigators publicly questioned whether the bones were authentic, the killer responded with something no detective expected: a photograph of the corpse, signed with a false name but bearing traceable handwriting. What followed was a cascade of communications that revealed a predator operating in plain sight, following funerals in real time and taunting authorities with knowledge only the killer could possess.
In this episode, we trace the 1988-1989 Saitama serial killings through the lens of a criminal investigation transformed by direct communication between perpetrator and family. We examine the contradictions embedded in the case: the handwriting evidence that arrived through the killer's own need for recognition, the escalation between the third and fourth murders that changed everything, and the psychiatric evaluation that concluded a man with severe dissociative traits was nonetheless fully criminally responsible. How does a brilliant child become invisible to the world, and what does it mean when that invisibility is finally broken through violence?
Victim: Mari Kono
Date: August 22, 1988 - July 23, 1989
Location: Saitama Prefecture, Japan
Status: Serial killer arrested and convicted
- Four girls aged four to seven disappeared over eleven months; the killer had no criminal record and lived with his parents
- The first three murders followed a pattern of escape; the fourth victim was retained at the killer's home, filmed, and partially cannibalized
- Miyazaki sent a package to the victim's family after police publicly doubted authenticity, then escalated to sending a photograph and attending the funeral while writing letters describing decomposition
- The killer's apartment contained over five thousand films, hundreds of mangas including extreme horror series, and his own recordings documenting the crimes
Mari Kono, Saitama Prefecture serial murders 1988, Tsutomu Miyazaki, child abduction, serial killer, Japan true crime, unsolved psychology, forensic investigation, criminal investigation, homicide, true crime English
To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com.
© 2026 OBOMEDIA. All rights reserved.
This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].
To listen ad-free and access premium episodes, start your 30-day free trial at obomedia.com
OBOMEDIA presents true crime storiesa true crime podcast built on real cases.
Every true crime story in our crime files follows the crime investigation from the missing person report to the trial: investigators and police building a murder case, a police investigation gone cold, justice for the victim and those who survived.
We open the unsolved murder, the cold case reopened decades later, the mysterious death, the disappearance, the serial killer, the family murder, the murder mystery; the missing persons a missing woman, a missing girl, a missing man found dead and the missing and murdered.
From the infamous case to the unsolved case, from classic true crime to dark true crime and disturbing true crime: true crime reports, real crime stories, real murder cases, true murder stories and unsolved mysteries one true crime case at a time, from the OBOMEDIA true crime vault.
© 2026 Created with OBOMEDIA technology. All rights reserved. This episode and its content (audio, text and related materials) are the property of their respective creator and are distributed under the OBOMEDIA name on platforms such as Apple Podcasts, Spotify, Amazon Music and Pocket Casts. Reproduction, distribution, editing or commercial use, in whole or in part, without prior written permission is prohibited. For permissions, licensing and business inquirie
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By Creator at ObomediaPolice Doubted the Bones Until the Killer Sent Her Photograph: The Serial Murders of Mari Kono
A box arrived at a Saitama family's doorstep containing ten baby teeth, underwear, and sandals-the remains of their missing four-year-old daughter. When investigators publicly questioned whether the bones were authentic, the killer responded with something no detective expected: a photograph of the corpse, signed with a false name but bearing traceable handwriting. What followed was a cascade of communications that revealed a predator operating in plain sight, following funerals in real time and taunting authorities with knowledge only the killer could possess.
In this episode, we trace the 1988-1989 Saitama serial killings through the lens of a criminal investigation transformed by direct communication between perpetrator and family. We examine the contradictions embedded in the case: the handwriting evidence that arrived through the killer's own need for recognition, the escalation between the third and fourth murders that changed everything, and the psychiatric evaluation that concluded a man with severe dissociative traits was nonetheless fully criminally responsible. How does a brilliant child become invisible to the world, and what does it mean when that invisibility is finally broken through violence?
Victim: Mari Kono
Date: August 22, 1988 - July 23, 1989
Location: Saitama Prefecture, Japan
Status: Serial killer arrested and convicted
- Four girls aged four to seven disappeared over eleven months; the killer had no criminal record and lived with his parents
- The first three murders followed a pattern of escape; the fourth victim was retained at the killer's home, filmed, and partially cannibalized
- Miyazaki sent a package to the victim's family after police publicly doubted authenticity, then escalated to sending a photograph and attending the funeral while writing letters describing decomposition
- The killer's apartment contained over five thousand films, hundreds of mangas including extreme horror series, and his own recordings documenting the crimes
Mari Kono, Saitama Prefecture serial murders 1988, Tsutomu Miyazaki, child abduction, serial killer, Japan true crime, unsolved psychology, forensic investigation, criminal investigation, homicide, true crime English
To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com.
© 2026 OBOMEDIA. All rights reserved.
This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].
To listen ad-free and access premium episodes, start your 30-day free trial at obomedia.com
OBOMEDIA presents true crime storiesa true crime podcast built on real cases.
Every true crime story in our crime files follows the crime investigation from the missing person report to the trial: investigators and police building a murder case, a police investigation gone cold, justice for the victim and those who survived.
We open the unsolved murder, the cold case reopened decades later, the mysterious death, the disappearance, the serial killer, the family murder, the murder mystery; the missing persons a missing woman, a missing girl, a missing man found dead and the missing and murdered.
From the infamous case to the unsolved case, from classic true crime to dark true crime and disturbing true crime: true crime reports, real crime stories, real murder cases, true murder stories and unsolved mysteries one true crime case at a time, from the OBOMEDIA true crime vault.
© 2026 Created with OBOMEDIA technology. All rights reserved. This episode and its content (audio, text and related materials) are the property of their respective creator and are distributed under the OBOMEDIA name on platforms such as Apple Podcasts, Spotify, Amazon Music and Pocket Casts. Reproduction, distribution, editing or commercial use, in whole or in part, without prior written permission is prohibited. For permissions, licensing and business inquirie
A box arrived at a Saitama family's doorstep containing ten baby teeth, underwear, and sandals-the remains of their missing four-year-old daughter. When investigators publicly questioned whether the bones were authentic, the killer responded with something no detective expected: a photograph of the corpse, signed with a false name but bearing traceable handwriting. What followed was a cascade of communications that revealed a predator operating in plain sight, following funerals in real time and taunting authorities with knowledge only the killer could possess.
In this episode, we trace the 1988-1989 Saitama serial killings through the lens of a criminal investigation transformed by direct communication between perpetrator and family. We examine the contradictions embedded in the case: the handwriting evidence that arrived through the killer's own need for recognition, the escalation between the third and fourth murders that changed everything, and the psychiatric evaluation that concluded a man with severe dissociative traits was nonetheless fully criminally responsible. How does a brilliant child become invisible to the world, and what does it mean when that invisibility is finally broken through violence?
Victim: Mari Kono
Date: August 22, 1988 - July 23, 1989
Location: Saitama Prefecture, Japan
Status: Serial killer arrested and convicted
- Four girls aged four to seven disappeared over eleven months; the killer had no criminal record and lived with his parents
- The first three murders followed a pattern of escape; the fourth victim was retained at the killer's home, filmed, and partially cannibalized
- Miyazaki sent a package to the victim's family after police publicly doubted authenticity, then escalated to sending a photograph and attending the funeral while writing letters describing decomposition
- The killer's apartment contained over five thousand films, hundreds of mangas including extreme horror series, and his own recordings documenting the crimes
Mari Kono, Saitama Prefecture serial murders 1988, Tsutomu Miyazaki, child abduction, serial killer, Japan true crime, unsolved psychology, forensic investigation, criminal investigation, homicide, true crime English
To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com.
© 2026 OBOMEDIA. All rights reserved.
This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].
To listen ad-free and access premium episodes, start your 30-day free trial at obomedia.com
OBOMEDIA presents true crime storiesa true crime podcast built on real cases.
Every true crime story in our crime files follows the crime investigation from the missing person report to the trial: investigators and police building a murder case, a police investigation gone cold, justice for the victim and those who survived.
We open the unsolved murder, the cold case reopened decades later, the mysterious death, the disappearance, the serial killer, the family murder, the murder mystery; the missing persons a missing woman, a missing girl, a missing man found dead and the missing and murdered.
From the infamous case to the unsolved case, from classic true crime to dark true crime and disturbing true crime: true crime reports, real crime stories, real murder cases, true murder stories and unsolved mysteries one true crime case at a time, from the OBOMEDIA true crime vault.
© 2026 Created with OBOMEDIA technology. All rights reserved. This episode and its content (audio, text and related materials) are the property of their respective creator and are distributed under the OBOMEDIA name on platforms such as Apple Podcasts, Spotify, Amazon Music and Pocket Casts. Reproduction, distribution, editing or commercial use, in whole or in part, without prior written permission is prohibited. For permissions, licensing and business inquirie