Stacey Joy Bourdeaux, 34, pleaded guilty last summer to manslaughter in the death of her 10-month-old son, Sean Ronald Fewer, and to the attempted murder of her five-year-old. She also admitted to failing to provide the necessities of life.
Bourdeaux admitted in her diary to both attacks. She was writing to her husband, Ted Fewer, who died a few years ago in an electrical accident.
"Dear Ted. Now that you are gone I can confess about Sean,'' Bourdeaux wrote. "The night that he left us, it wasn't actually while he was sleeping.
"I did what I didn't want to do. The crying wouldn't stop, so I ended up putting a pillow over his face and made sure that it was stopping his breathing. I know it's something that I shouldn't have done, but I did.''
Friday was the continuation of sentencing arguments from earlier this month.
Crown prosecutor Janice Rea suggested that after Bourdeaux was arrested, she attempted to minimize her actions about smothering her son in 2004. Rea urged Justice Terry Semenuk to rely on the accused's own words in her journal.
"Common sense dictates what a person enters privately in a journal is truthful. She would have no reason to lie."
Rea said there was also little sign of remorse.
"There's no mention of the death being a mistake or an accident," she said.
"It is a clear statement of her intention which approaches murder."
The Crown is asking for a sentence of 18 years for Bourdeaux. The defence has said the sentence should be in the eight- to 10-year range.
Defence lawyer Katherin Beyak told court that her client had a "traumatic upbringing" and was sexually and physically abused by family members as a child.
She said Bourdeaux is below average intelligence, has had substance abuse problems and received little or no psychological counselling for the abuse she endured beginning at age 6. The impact of her upbringing made it difficult for her to cope when she became a mother herself, Beyak said.
"We're at the lower end of moral culpability," she said.
"Her thought processes were disrupted. We're not dealing with an average, everyday, fully functional person."
Beyak said Bourdeaux had been "acting out" and has reacted well to counselling and after being prescribed anti-depressants.
Ten-month-old Sean was found not breathing in his crib in December 2004. At the time, his death did not raise any suspicion with the medical examiner, who ruled it was a case of sudden infant death syndrome.
In May 2010, police were called to Alberta Children's Hospital in Calgary where a five-year-old boy was brought in with breathing trouble.
A few months later, police charged Bourdeaux with attempted murder and choking with intent. They looked into her background and that's when they discovered Sean's death.
The attack on her five-year-old came after her husband was already gone. The Crown concedes that Bourdeaux was going through a serious depression.
"I was trying to send him to you,'' she wrote. "And if I lose him now, I am going to feel really bad, 'cause it would be my fault. I can say he's very tough and a fighter.''
Court heard Bourdeaux dragged the boy upstairs after he had thrown a tantrum. Over a two-hour period, she attempted to choke him to death.
She waited several days before taking him to hospital. He survived, but has severe brain damage, no longer speaks and has limited motor skills.
"The injuries suffered ... are nothing short of catastrophic and that is an aggravating factor," Rea said. "The important distinguishing factor is the intention to kill," she added.
"I'm suggesting everything in the diaries, including the thoughts of suicide, should be accepted. The statement that she held the pillow over his face until he stopped breathing should be accepted.
"She was very angry and ready to kill."
The defence is to continue its submission Monday.