Three days before nine-year-old Amber Lucius was drugged and burned alive by her mother, her parents' divorce was finalized, confirming her father would have full custody.

"I miss my daughter with my whole heart," said Duane Lucius in his victim impact statement on Friday. "I still remember the first day I held her in my arms."

Laura Coward, 50, was originally charged with first-degree murder but Calgary Court of Queen's Bench Justice Scott Brooker accepted a plea to second-degree murder in February.

"I will never forgive her and I will never forget my daughter," said Lucius.

In 2007 Coward left her husband Lucius and took Amber — then two years old — with her.

Right away, Lucius started fighting to see his daughter.

"I did everything the court said," he told the judge at his ex-wife's sentencing hearing.

By 2013, Lucius was awarded sole custody of his daughter, who he said was thrilled to be on the farm with her dad. She was supposed to see her mother every other weekend.

"Laura never thought that was enough," said Lucius.

Trauma dog accompanies Amber's sister

With a photo of his dead daughter beside him, Lucius stood in the courtroom's witness box and told the judge he struggles to be strong.

"The saddest day of my life ... was when I was told Amber was found dead in an SUV."

During the sentencing hearing, Amber's now-17-year-old sister watched the proceedings from a remote witness room.

The girl — too fragile to be in the same room as her mother — was accompanied by her father and the RCMP trauma dog, Ringo.

The girls have the same mother but different fathers. Coward left her older daughter with friends on the night of Aug. 30, 2014, before drugging Amber with the sleeping medication Zopiclone and setting the truck on fire while the girl was alive.

Laura Coward's vehicle, where Amber's body was found. (Court exhibit)

Amber's stepmother, two aunts and an uncle also wrote victim impact statements that were read in court Friday.

"​[Coward] not only stole Amber's life but all of our dreams for her future. She replaced those dreams with nightmares," wrote one of her aunts, Corinne Ward.

Randal Lucius said his brother has been "depressed, withdrawn and solemn" since Amber's death.

Shortly before that, Duane Lucius had been awarded full custody of his daughter following a lengthy court dispute.

"This is where I want to be," Amber told her father after a judge awarded him custody in June 2013.

'I beg for their forgiveness'

Prosecutors Mac Vomberg and Jillian Pawlow have proposed a life sentence for Coward with no chance of parole for 20 years.

Defence lawyer Jim Lutz has proposed a parole ineligibility of 10 to 12 years.

Coward's guilty plea should be seen as an expression of remorse, said Lutz.

At the end of the sentencing hearing, Coward was given the chance to address the court.

"Every day and every moment I miss my children more than anyone will ever understand," she said through tears.

Then Coward turned toward her family in the gallery.

"I'm responsible for my choices ... I beg for their forgiveness and I plea for your mercy."

Laura Coward, 50, will be sentenced next Friday. (Jane Fletcher)

Amber was found dead in a car on a rural road near Sundre, about 100 kilometres northwest of Calgary, in September 2014.

The girl had been visiting her mother on the Labour Day long weekend and was supposed be returned to her father two days before her body was found.

Coward told friends and her other daughter she was going to take Amber star gazing, but drove to a Tim Hortons and then to a rural property.

She gave her daughter sleeping pills that she had stolen from a friend.

While Amber was unconscious inside the SUV, Coward stole a propane torch from a nearby trailer and set it on fire.

The child died of smoke inhalation.

3 first responders have PTSD

Coward showed "an astounding level of commitment" to murder Amber, said Pawlow in her submissions and called the crime "a senseless and unimaginable nightmare."

Three first responders — two RCMP investigators and the fire investigators — are on long-term medical leave as they deal with post-traumatic stress disorder, court heard on Friday.

A hang-up 911 call on Sept. 2, 2014, led RCMP to the car, which was parked on a friend's property.

Officers arrested Coward as she emerged from the friend's home wrapped in a blanket.

The judge will announce his decision on Coward's sentence next Friday at 1:00 p.m.