A Perth mother will spend at least 18 years in jail for stabbing her husband to death as he slept in their home, before turning the kitchen knife on two of her young sons.

Cara Lee Hall, 38, was found guilty last year of murdering 33-year-old Glenn Hall at the family's home in the southern Perth suburb of Leda in December 2015, before attacking two of their four sons, who at the time were aged 11 and 4.

Mr Hall was stabbed more than 16 times as he slept on a mattress.

Hall then called triple zero and said she had stabbed her husband because he was trying to kill her and their children.

The Supreme Court was told that during the call Hall could be heard telling her sons to go to a neighbour who would keep them safe, and she later told detectives she had not been able to bring herself to kill them.

Killer was 'psychotic' during attack

At her trial, Hall claimed she had acted in self defence because she had endured years of physical and mental abuse and feared her husband was going to kill her and the children.

But, during the sentencing process, psychiatrists determined she was suffering a "trauma-induced psychotic episode" before, during and after the attack.

The court heard Hall was having paranoid delusions that her husband was trying to kill the children or that he was trying to sell them into the sex trade.

She also claimed she was hearing voices from God and the Devil.

Hall's lawyer, Mara Barone, submitted that because of her client's mental illness she should not receive a life jail term, but should instead be given a finite sentence.

But state prosecutor Brett Tooker argued Hall's mental condition was affected by her use of drugs, including methamphetamine and cannabis, which she said she had smoked the night before the murder.

Mr Tooker said given Hall had in the past been diagnosed with "drug-induced psychosis" she had "clearly been aware of the link" between drug use and her mental health and "must in part be held responsible".

Cara Hall and Glenn Hall, who she murdered at the family's Leda Home in December 2015. ( Facebook: Cara Hall )

A 'brutal and savage' attack

Justice Michael Corboy accepted that Hall suffered serious psychological and psychiatric illnesses because of her traumatic and dysfunctional upbringing, but he ruled it would not be "unjust" to impose a life jail term.

He found that while Hall, in her psychotic state, did believe her husband was going to harm her and her children, that was not a reasonable belief.

"You did not have reasonable grounds for thinking it was necessary to stab him multiple times," he said.

Justice Corboy also said Hall knew from past experience that using illicit drugs affected her mental state and wellbeing.

He described the murder as "brutal and savage", saying Hall had subjected her husband to a frenzied attack.

Justice Corboy also said the attack on her sons must have been "extraordinarily frightening and terrifying" and was likely to be something that would mark them for the rest of their lives.

A restraining order is in place banning Hall from ever having contact with her two sons.

Several members of Mr Hall's family and friends were in court to hear the sentence, wearing t-shirts with photos of him printed on the front.

Family and friends of Glenn Hall wear t-shirts with his picture on as they leave court following the sentencing. ( ABC News: Joanna Menagh )

When the sentence was read out and Hall was led away, one shouted: "Rot in hell, bitch."

Outside court, Mr Hall's brother Jamie spoke to reporters.

"It's been a terrible tragedy what's happened to our family and we'd just like to thank the DPP and everyone else who's been involved in this case," Mr Halls said.



Friend defends 'beautiful person with a heart of gold'

A friend of Hall's, Wendy Lourenco, spoke outside the court after the sentencing.

"There was (sic) no winners or losers here today, everybody lost something … but I support my friend and I'll be visiting her while she's in jail," Ms Lourenco said.

She described Hall as a beautiful person whom she loved dearly.

"Everyone has a different opinion, everyone is entitled to their opinion. Mine is that she's a beautiful person with a heart of gold."