05/19/2016 18:29 EDT | Updated 05/20/2017 01:12 EDT

Testimony concludes in trial of mom who slit her five-year-old son's throat

SASKATOON — Testimony has wrapped up in the first-degree murder trial of a woman accused of slitting the throat of her five-year-old son.

The defence argues that Kellie Johnson is not criminally responsible for her actions due to mental illness while the Crown has presented evidence suggesting she knew and understood what she was doing.

Dr. Mansfield Mela and Dr. Lindsay Robertson both testified for the defence Johnson didn’t know the difference between right and wrong when she killed her son, Jonathan Vetter.

They said she truly believed she was doing the right thing, and Robertson said Johnson was “acutely psychotic” at the time.

Crown witness Dr. Olubankole Obikoya disagreed, telling court he believes Johnson knew her actions were legally and morally wrong and could understand the nature of what she did.

He said Johnson buying a knife two weeks before the killing shows she had the intellectual capability of planning and executing the killing, and that she had the capacity to make choices.

She also showed some signs of guilt after the killing, he said.

Court heard Johnson hadn’t been taking her medication for at least a month before the killing and that, beginning in 2006, she began hearing and seeing things that didn’t exist.

Johnson told all three doctors about “the woman" — an imaginary person who Johnson believed worked for the devil.

Johnson believed the woman was going to kill her, leaving her son to be raised by her ex-boyfriend, who she believed would molest the boy, which would lead the child to become a molester himself and land him in hell.

She told the doctors that in order to save the boy from hell, she had to kill him first so he would go to heaven.

Johnson will remain in Saskatchewan Hospital for now. Closing arguments in the case are scheduled for Aug. 19.

(CTV Saskatoon)