A Saskatoon courtroom was left in tears Wednesday as it heard the upsetting first-person account of how a 16-year-old girl murdered baby boy Nikosis Jace Cantre in July 2016.

The details came in a videotaped testimony given by the youth a week after she was arrested for the murder. She has already pleaded guilty to second-degree murder.

The youth — who can't be named under the Youth Criminal Justice Act — covered her own ears as tape of her testimony was played by a Crown attorney who had warned the video "will be difficult for the family to hear."

Beaten and stabbed 

The youth had ended up at the Cantre home after running away from open custody at Kilburn Hall, a youth detention facility in Saskatoon.

Before arriving at the Cantre residence, she had smoked marijuana she thought had been laced with meth.

Once inside the home — after being invited in by the family — the teen drank vodka while the rest of the house was asleep.

The teen heard the baby, Nikosis, crying. She says she then beat and stabbed the child before leaving the room.

"I let all my anger out on that baby," she said on the tape.

She remembered being confronted by Cantre's mother.

"I heard her saying, 'Oh my God, oh my God, that girl did something to my baby,'" she said.

Adult sentence sought

The little boy died of a blunt-force trauma.

His grandfather, Jeffrey Longman, says the family is shattered.

"You wake up every day in pain," he said. "I've got no words that explain how I feel. He was just a baby. He was six weeks old. We had just brought him into our home."

The Crown is seeking to have the young woman sentenced as an adult.

At one point in her taped confession, the teen said, "I'm sorry."

Missed her own family

She said that she had hurt animals when she was younger and that she'd even been violent toward her own niece.

She was serving a 10-month sentence for a range of offences, including assault causing bodily harm and assault with a weapon.

She also said that she had been in a group home since she was 11 and that she never saw her biological family, and that she ran away from Kilburn Hall because she missed her family.

Her sentencing hearing will continue next week.

with files from Charles Hamilton and Dan Zakreski