A Calgary couple who beat a six-year-old girl to death over the course of a weekend executed "cruel, degrading" acts of discipline during which the child was confined, and so they are both guilty of first-degree murder, the Supreme Court of Canada has explained.

Spencer Jordan and Marie Magoon spent days torturing Jordan's six-year-old daughter, Meika Jordan.

The couple appealed their first-degree murder convictions to the country's highest court. In November, the full panel of Supreme Court judges spent only a few minutes deliberating before deciding to uphold the convictions with reasons to follow. On Friday, those reasons were released.

"The acts of "discipline" were grossly disproportionate, cruel, degrading, deliberately harmful, and far exceeded any acceptable form of parenting," reads the decision.

The weekend of Nov. 11, 2011, began when Meika's stepmother held a lighter under the child's palm. The girl was visiting her father and Magoon for a few days before she was supposed to be returned to her mother and stepfather.

To hide the burn from Meika's mother, Jordan and Magoon did not return the child as per their custody arrangement.

Over the next few days, the violence increased; Meika was punched and tripped, and her head was slammed off a tile floor. She was dragged up and down the stairs by her hair and forced to run the stairs as a punishment.

On Nov. 13, 2011, Jordan called 911, telling first responders his daughter — who was unconscious and in respiratory arrest when paramedics arrived — had fallen down the stairs.

Meika died in hospital the next day from blunt force trauma to her head and internal injuries to her pancreas and liver.

After a lengthy undercover police investigation, Magoon and Jordan were arrested more than a year later.

They were charged with first-degree murder but found guilty of the lesser offence of second-degree murder. The Crown appealed and the Alberta Court of Appeal elevated the conviction to first-degree murder, finding the girl was forcibly confined leading up to her death.

Lawyers for Magoon and Jordan had argued that first-degree murder and second-degree murder are simply sentencing designations and that the Alberta Court of Appeal didn't have the jurisdiction to elevate the couple's convictions.

The Supreme Court disagreed: "The Crown is arguing that the elements of the offence have been made out, not that the accused should have received a longer sentence or period of parole ineligibility."

"First-degree murder and second-degree murder are to be treated as two distinct offences," reads the decision.

The Supreme Court also dealt with the nature of a parent/child relationship in assessing whether forcible confinement occurred. The court reasoned that parents are lawfully entitled to restrict the liberty of their children but that authority has limits.

"If a parent engages in abusive or harmful conduct toward his or her child that surpasses any acceptable form of parenting, whether or not physical violence is inflicted, the lawfulness of his or her authority to confine the child ceases.

"In those circumstances, the lawful authority is transformed into unlawful authority because it represents the exploitation of authority for an improper purpose."

In the end, the decision finds that "the unlawful confinement and murder were two distinct criminal acts that formed part of a single transaction" in upholding the convictions.

A first-degree murder conviction carries an automatic life sentence with no chance of parole for 25 years.