Years before Jacqueline Danielle Henderson walked into the bedroom of six-week-old Nikosis Cantre and killed the baby in his sleep, she showed disturbing signs of violence.

The teen girl's identity—and the full details of her disturbing past heard during a sentencing hearing in Saskatchewan provincial court in Saskatoon—can now be revealed for the first time.

At 11 years old, Henderson began torturing animals and admitted skinning and hanging them alive.

Later, while in foster care, she stole a mouse from a pet store, brought it home and squeezed it to death.

She lit fires and got into fights with other kids at the various group homes where she lived, court documents show.

Nikosis Cantre's grandfather Jeffery Longman, left, with supporters outside Saskatoon provincial court. (Devin Heroux/CBC)

A shocking crime

Henderson was 16 when she met Mellisa Bird, a relative of Nikosis, at a party around 6 a.m. on July 2, 2016. Henderson had escaped the open custody wing of Saskatoon's youth jail hours earlier, according to an agreed statement of facts presented to the court.

Inmates in the open custody wing can move freely, but are under constant supervision and need permission from a supervisor to leave.

The teenager had been wandering the streets before she found the party on the 200 block of Avenue N South in Saskatoon.

Everybody will know her name, so everybody will know who she is, that what she did was wrong and [so] that this will never, ever happen again. That's what I want. - Jeffery Longman , Nikosis's grandfather

Bird bought her dinner and offered her a place to sleep. She'd never met the teenager before that night.

Less than 24 hours after that fateful meeting, the unthinkable happened.

Unprovoked, Henderson entered Nikosis's bedroom while the rest of the family was sleeping.

She then beat, stabbed and stomped him to death.

Henderson pleaded guilty to second degree murder in the baby's death. During her sentencing hearing last December, the court watched a police interview of the teen confessing to the killing.

Last month, the now 18-year-old was given an adult sentence for the brutal killing: mandatory life in prison.

Her name has remained under a publication ban during the sentencing hearing and for the 30-day post-sentencing appeal period, which expired Thursday. Henderson's lawyer, Brian Pfefferle, did not appeal the adult sentence, and the publication ban was lifted.

Nikosis's grandfather said at the time of the sentence he was pleased Henderson's name would finally be made public.

"Everybody will know her name, so everybody will know who she is, that what she did was wrong and [so] that this will never, ever happen again. That's what I want," Jeffery Longman said outside court on Feb. 27.

A childhood filled with cruelty

Henderson was born on Oct. 18, 1999, in Saskatoon and is a member of the Montreal Lake Cree Nation.

A Gladue report filed with the court said that shortly after her birth, her biological mother said, "get that thing away from me!"

Gladue reports are designed to give judges options to give Indigenous offenders an alternative to jail time, and often outline an offender's life, focusing on tragic events that may have led to a life of crime.

Henderson was adopted by her biological aunt and referred to her as her mother. Years later, she was diagnosed with fetal alcohol spectrum disorder.

In 2010, when she was 11, she was taken away from her aunt after she was caught skinning and killing small animals, according to the Gladue report.

Then began Henderson's life in the foster care system.

She bounced back and forth between foster homes for most of her teenage years. Starting when she was 12, she spent several years in group homes, the report says.

She told investigators and authors of the Gladue report that she was sexually abused by a 14-year-old boy when she was in foster care in northern Saskatchewan.

She also reported at various times being sexually abused by family members.

During Henderson's sentencing hearing, the court also heard she was prone to self-harm, once leaving a needle in her arm until it festered. On another occasion, Henderson swallowed a pair of tweezers that had to be removed by surgery.

While in custody, she also faked seizures and faked drowning in a bathtub.

She often lied and "engaged in sexually inappropriate behaviour," including joking about incest, according to a psychological court report prepared on Aug. 23, 2016, a month after the killing.

Despite her time in foster care, Henderson did have some contact with her family.

Once, while she was staying at her cousin's house, she fed her younger cousin morphine pills. The younger cousin overdosed and almost died.

Court documents detail criminal past

While there were signs of violence for years before the brutal killing, Henderson's criminal history started in earnest in January 2015.

A court-ordered intensive custody rehabilitation and supervision assessment says Henderson was staying at a group home in North Battleford called Crystal's Home. The report says Henderson "started a fire, which essentially made Crystal's Home unlivable."

That was her first real criminal offence, but from there, she was in and out of custody. She ran away from open custody facilities on more than one occasion, the report says.

When she escaped Kilburn Hall, a youth custody facility in Saskatoon, on July 2, 2016, Henderson was serving a 10-month sentence for a range of offences, including assault causing bodily harm and assault with a weapon.

Those charges stemmed from an altercation she had with two youth workers in North Battleford, the court heard.

She spent several hours wandering the streets, meeting strangers. She told police she met someone at a skateboard park and that this unidentified man shared a joint with her that was laced with meth.

Henderson claims the man later raped her while the two were sleeping on a cardboard box by the river.

Hours later, she met Bird at a party at a west side apartment building.

Bird offered the teen a ride and bought her a meal and tried to take her to Egadz, a youth outreach centre. The centre was closed, and Bird invited Henderson to the Cantre house. (It was unclear from court documents whether Bird lived at the house or simply had relatives there.)

Flowers, stuffed animals and a poster acted as a memorial for Nikosis Cantre. (Chanss Lagaden/CBC)

The family agreed to let Henderson stay at the house until they could find her somewhere else to live.

It was just after 6 a.m. the next morning on July 3, while many in the family were sleeping, that Henderson heard the baby crying. She went into his room and found the baby in his playpen, crying. She cradled the infant and tried to feed him with a bottle, according to Henderson's interviews with investigators.

Then she beat, stabbed and stomped the baby to death.

Nikosis died of blunt force trauma.

Henderson then tried to hide the baby's blanket, which was covered in blood. She put the baby back in his playpen where she found him.

Judge said teen had 'ability to control' her actions

Over the course of her sentencing hearing, Henderson offered no explanation for the killing.

She told police officers that she was angry.

"I let all my anger out on that baby … I was so sick and tired of life … that's why I hit that baby, that's why I killed it," Henderson said during a videotaped interview with police—days after the killing—that was shown in court.

At one point in court, Henderson said she was "truly sorry" and that "if this happened to my baby, I would be very devastated."

Cantre's family did not accept that apology.

Henderson's lawyer argued during her sentencing hearing that the combination of fetal alcohol spectrum disorder, her age and her troubled childhood—which included sexual abuse—made her "incapable of really controlling her behaviour and thinking."

In explaining the decision to sentence her as an adult, Judge Sanjeev Anand said Henderson's age and cognitive issues didn't excuse her actions that night.

"You had the ability to control your actions. You didn't," Anand said directly to Henderson.

Henderson is serving a life sentence and will be eligible for parole in seven years.