Pauline was worried her 9-year-old son was a serial killer. This week she was murdered.

“She told her doctor one time she was so scared she was raising the next serial killer.”

Pauline Randol, 51, has a nine-year-old adopted son.

He’s in second grade, and has a history of mental health problems. He came from a troubled home, and only joined Randol in hers three years ago.

Recently, he started snapping, and it was terrifying her.

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She had been begging for help from professionals in their home county of Michigan, USA.

She’d finally got an appointment for Tuesday, but it was wasn’t soon enough.

On Monday morning, the boy, whose name hasn’t been revealed due to his age, allegedly shot his mother dead with a rifle he found inside the house.

On Tuesday, he was charged with murder.

Harley Martin, Randol’s daughter, told 24 Hour News 8, he “doesn’t know what he did”.

“He doesn’t understand why he can’t come home or anything,” she insisted. “He’s traumatised by what he saw in there.”

In the court appearance in which he was charged with her murder, he turned to his sister and asked “Where’s mum?”

Martin insists this is not something her brother did to be spiteful or mean.

“He’s not a bad kid,” she told the news station. “I don’t want people thinking bad of him, I know she still loves him.”

She said her mother was scared he was a serial killer.

Martin called her adopted brother “a sweet, caring young man who needed help further than the help my mother gave him, and she tried”.

“My mother’s death lays in the hands of people failing to educate in mental issues and failing to listen when helped is being begged for,” his other sister Reagen Martin, 23, told Detroit News.

The little boy is also accused of threatening to kill an eight-year-old child in 2018.

“He told her that he wanted to get a knife and stab her and watch her die, and watch her mother cry,’ the girl’s mother Alecia Pieronski told the nydailynews.

“My want was to remove him from the school and protect the children. I do feel in my whole heart the teachers and principals did everything they could do.”

The accused child is currently undergoing psychiatric evaluation at a state-run juvenile facility.

Children who kill.

It is rare for a child to commit a serious crime, and even rarer for a child to commit murder.

But it does happen.

In fact, American statistics claim the number of young children who kill is rising.

In 2008, the murder arrest rate was 3.8 per 100,000 juveniles. That’s 17 percent more than 3.3 in 2004.

However the all time high was in 1993, when the arrest rate peaked at 14.4.

Some of the reasons put forward as to why children murder include severe mental illness, how they grew up, or biological causes like brain damage and head trauma.

Lionel Tate, 12.

In 1999, Tate was left alone with six-year-old Tiffany Eunick who was being babysat by his mother.

He stomped on her until she died, and was the youngest American citizen to be sentenced to life in prison without the possibility of parole.

The little girl suffered a lacerated liver, a fractured skull, broken rib and a swollen brain.

His conviction was overturned in 2004 on the basis that his mental competency had not been evaluated before the trial. He was released on a year's house arrest and 10 years probation before going back inside for further crimes.

He was due for release in 2018.

Jordan Brown, 11.

In Pennsylvania in 2009, Brown murdered his father's 26-year-old fiance Kenzie Houk, who was eight months pregnant.

He shot her in the back of the head using a gun given to him by his father.

Prosecutors speculated that Brown killed his stepmother because he was angered by the pending birth of a new sibling and was jealous about the attention his stepsisters received.

In 2018, he was exonerated because the court determined that the evidence at the crime scene could have been planted by an unknown assailant.

Eric Smith, 13.

Smith had intermittent explosive disorder, a mental disorder that causes individuals to act out violently and unpredictably.

While riding through a local park in New York in 1993, he lured four-year-old Derrick Robie into a wooded area where he strangled him, dropped two large rocks on his head and sodomised his body with a tree limb.

He has been refused parole eight times since 2001.

Psychologists believe he will never be fully rehabilitated.

Mary Bell, 11.

In 1968, Mary Bell strangled three-year-old Brian Howe to death.

She'd had a troubled upbringing, her mother had tried to kill her on more than one occasion, trying to make it look like an accident. Once she gave her pills pretending they were sweets.

She also says she was subjected to repeated sexual abuse, and forced to engage in sexual acts with men by her mother who worked as a prostitute.

After serving her 12-year sentence, Bell was released in 1980, and has lived under a series of pseudonyms.

John Venables and Robert Thompson, 10. 

In 1993, the two 10-year-old's abducted toddler James Bulger from a shopping centre in Merseyside, England.

They took him to a disused railway line where they tortured him.

They threw paint in his eye, kicked and stomped on him, threw bricks and stones at him, then dropped a 10kg iron plate on him.

He had 42 injuries in total, and the pathologist involved couldn't isolate which was the fatal injury.

They were released in 2001 aged 18, and given new identities to protect them for life.