Over this time, the man would hit his step-daughter until she got into a very cold bath and forced her to stay in it for long periods while her mother stood by.
"I'm satisfied that she came close to hypothermia at times," Judge Rob Ronayne said. "She stopped counting at about 30 such baths."
The man also forcibly cut the girl's hair and told the woman to braid what was left to hide the bald patches.
"She described all of her hair being cut off, I accept that that did not literally happen. But in my view, it was a young girl's perception of your cruel and degrading treatment, cutting chunks out of her hair," Judge Ronayne said.
On one occasion, the stepfather grabbed the teenager in a bedroom and held his hand over her mouth and put his hand around her neck until her vision went blurry and she struggled to breathe.
He told her she was garbage and that she would never grow up - the bedroom would be her cemetery.
On another occasion, the couple tied the teen up with an electrical cord and when she loosened the bonds, they were re-tied which caused her pain in her legs and she struggled to walk afterwards.
"[In another incident] in her room where you [stepfather] grabbed her, you pushed her down, hurting her arm. You locked the door with a chair, you pinned her from behind. She mentioned you trying to take her pants off. She fought you and she hit you so hard she hurt her own arm.
"I'm quite satisfied there is an element of indecency in these assaults. They had a sexual theme to them," Judge Ronayne said.
He also trusted the teenager's testimony, saying her victim impact statement revealed someone who was "fortunately a resilient young woman" and that he found her to be a "careful and particular and honest witness in every respect".
When the couple were interviewed by a probation officer after being found guilty of a number of charges relating to the abuse, they said they believed the teenager to be a witch and their behaviour was a common practice in the Congo.
The probation reports said neither defendant showed any remorse, care or accountability for what they had done and recommended prison sentences because the man was at a high risk of reoffending and the woman was a moderate risk.
The woman's lawyer submitted she had a "hard life" as a refugee and was isolated from her family and that she acted because she thought her daughter was possessed.
The judge did not accept this excuse and later called her belief in witchcraft a "fallback".
Before he sentenced the duo, Ronayne said there was a need to denounce this type of abuse of vulnerable children and a "need to bring home" that they were responsible for what took place and to be held accountable for what they'd done.
He told the man: "The reality is that you have an ingrained belief system which you variously use sometimes and deny at other times depending on what suits you in the circumstances. You are not being honest at all."
The man was sentenced to 2 years and three months in prison for jointly intentionally engaging in conduct that would harm the teenager, four months for the male assaults female, nine months for a representative charge of male assaults female and three months for common assault.
The woman was sentenced to one year and nine months for jointly intentionally engaging in conduct that would harm the teenager and three months for common assault.
