At 10, Armarjeet Sada was the world's youngest serial killer. No one knows where he is.

As far as serial killers go, Amarjeet Sada is the world’s youngest, and probably one of the most efficient — and heinous — killing three children between 2006 and 2007.

By the time he was 10, Sada had murdered three children in the span of twelve months; and one of them was his baby sister.

Little is publicly known about the young boy born in 1998, from the relatively small farming town of Begusarai in the state of Bihar, India. Much about him was suppressed in court because of his age.

We do know that Sada’s father was a labourer, the family were regarded as impoverished and none had consistently attended school.

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And that, for some reason, the boy was motivated to beat his six-year-old cousin and eight-month-old sister to death in 2006, and in 2007, Kushboo, a six-month-old baby.

What did the world's youngest serial killer, Armarjeet Sada, do?

According to The Sun, Sada’s uncle revealed the family were aware of the first two crimes but kept them private as "family matters" to protect Sada.

But they could no longer hide his heinous actions and protect him from the consequences after he murdered an infant, Kushboo.

The baby’s mother, Chunchun Devi, told police she left her baby in care, sleeping, at a local primary school in 2007. When she returned, Kushboo was missing.

Not long after that, Sada — a neighbour of the Devi family — faced allegations by those in his community. They knew he had a ‘dark streak’ and had previously suspected him in the deaths of the other children in his family. The villagers were responsible for calling the police to speak to Sada, but authorities initially didn’t believe that such a young child could know anything about a missing baby.

Under pressure to tell the truth, Sada’s parents eventually allowed their son to admit that he strangled Kushboo, hit her with bricks and buried her in a shallow grave.

As he was able to lead authorities to the recently buried baby, they believed him when he also revealed he’d previously murdered his little sister and cousin. Investigations eventually revealed all children had been murdered by beating.

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What did Armarjeet Sada say about his killings?

At his first interrogation with police, it was reported that Sada asked for a biscuit and that he didn’t seem nervous or remorseful. He was also unemotional when telling them about Kushboo’s murder.

“She was sleeping in the school. I took her a little away, and killed her with a stone and buried her,” he told them.

The Times of India reported that a psychologist who assessed Sada and diagnosed him with a general childhood psychiatric disorder, called him a “sadist who derives pleasure from inflicting injuries.”

How the Indian juvenile justice system handled Amarjeet Sada's case.

Sada posed a judicial and custodial problem because of his age.

According to The Guardian, Sada was placed in a remand home because, under Indian law, a child cannot be sentenced to death or sent to prison, but can be detained at a children's home until they turn 18.

This was the case for Sada, where he apparently had access to the medication and treatment he needed. He was also apparently held in solitary confinement for much of this time.

What happened to Amarjeet Sada, the world's youngest serial killer?

Sada was released in 2016 upon his eighteenth birthday, but according to reports, his whereabouts are unknown. He would now be around 26 years old.

While there have been numerous other cases of very young children committing murder, such as the 10-year-old killers of toddler James Bulger, none have done so multiple times – or had the chance to do so… or been caught.

Are there any other young serial killers?

Mary Bell.

Mary Flora Bell is Britain's youngest female killer, committing her first murder at age 10 in 1968 in Scotswood, Newcastle upon Tyne.

Born on May 26, 1957, to Betty McCrickett, a 16-year-old sex worker, Mary endured severe abuse and neglect during her formative years. Betty had attempted to give Mary away but refused to let family members adopt her.

On May 25, 1968, the day before her 11th birthday, Mary committed her first murder, strangling four-year-old Martin Brown in an abandoned house. Following the murder, she displayed disturbing behaviour, including asking to view Martin's body in his coffin and leaving confession notes that police initially dismissed as pranks.

Two months later, Mary, along with her friend Norma Bell (no relation), killed three-year-old Brian Howe. This second murder showed escalation, as the victim was not only strangled but also mutilated.

In December 1968, at age 11, Mary Bell stood trial at Newcastle Assizes. While her friend Norma was acquitted, Mary was convicted of manslaughter on grounds of diminished responsibility after being diagnosed with psychopathic personality disorder. The prosecution argued that she committed the murders "solely for the pleasure and excitement of killing".

Mary served 12 years in custody, being released in 1980 at age 23. She was given a new identity and released on license, effectively remaining under supervision while living in the community.

The courts granted her a lifelong anonymity order, which was later extended to protect her daughter and granddaughter.

Craig Price.

Craig Price, known as the "Warwick Slasher," holds the disturbing distinction of being the youngest serial killer in U.S. history.

Born on October 11, 1973, in Warwick, Rhode Island, Price committed his horrific crimes between the ages of 13 and 15.

At just 13 years old, Price committed his first murder on July 27, 1987. He broke into the home of Rebecca Spencer, a 27-year-old mother of two who lived just two houses away from him, and stabbed her 58 times. The murder went unsolved for two years.

On September 1, 1989, at age 15, Price struck again in an even more brutal attack. He murdered Joan Heaton, 39, and her two young daughters, Jennifer (10) and Melissa (8). The violence was extreme — Joan was stabbed 57 times, Jennifer 62 times, and Melissa suffered 30 stab wounds along with a crushed skull. The attacks were so savage that knife blades broke off inside the victims' bodies.

Police caught Price through a combination of evidence — a deep cut on his hand that he couldn't explain, his size-13 footprints at the crime scene, and bloody knives found in his backyard shed.

When confronted, Price confessed to all four murders with a chilling lack of remorse, describing the killings in a nonchalant manner that deeply disturbed investigators.

Despite the initial law requiring his release at 21, Price has remained imprisoned due to his violent behavior behind bars. He has been involved in numerous incidents including jail stabbings and remains behind bars, currently serving a 25-year sentence for stabbing another inmate.

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