Victoria reconnected with a friend from church. He was planning her murder.

Victoria Stewart was a caring woman. She laughed lots and loved hard, especially when it came to her family.

The mother-of-five, 39, was a member of her local Jehovah's Witness congregation in Adelaide, where she first met Clifford Arthur Neumann, 41.

After 15 years, the pair reconnected on Facebook in August 2023 and struck up a friendship.

Just four months later, an obsessed and jealous Neumann took Victoria's life in a ferocious and premeditated attack.

In the South Australia Supreme Court this week, Justice Laura Stein said Neumann later told a forensic psychologist he hoped Victoria would leave her partner to be with him.

"However... you became increasingly suspicious that Ms Stewart was hiding things from you and was still in a relationship with (her partner)," Stein said.

When Victoria visited his Morphett Vale home on November 19, Neumann enacted a "clearly premeditated" plan to kill her with a steel bar.

After being "wracked with guilt and grief" for Victoria and her children, Neumann called police and told them he had done a "horrible thing" and was sorry.

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An "abhorrent" murder.

Stein chose to spare Victoria's family from hearing the graphic details of the horrific murder in court but said the 41-year-old attacked Victoria with "ferocity" and described the incident as "abhorrent".

"[It] was brutal and frenzied, and blows were delivered with terrible force," Stein said.

"She trusted you and she was vulnerable.

"You carried out the attack on a defenceless woman who could do nothing to fend you off."

Forensic psychologist Loraine Lim found there was likely to be a direct link between his "mild to medium level" autism, and developing an obsessive plan to kill Victoria.

"Dr Lim considered your restricted capacity for perspective-taking and empathy, as well as poor inherent understanding of human emotions and behaviours and an inability to appreciate social cues, most probably caused you to grossly misinterpret the changes in Ms Stewart's behaviour," Stein said.

However, while relevant, Neumann's autism diagnosis did not significantly reduce his moral culpability or moderate the need for denunciation or deterrence, she added.

"You knew you were planning to do a bad and horrible thing, you knew the consequences," Stein said.

The judge accepted Dr Lim's assessment that Neumann had prospects for rehabilitation, including his insight into the unforgivable impact of his conduct, his guilty plea, his generally non-confrontational personality, lack of any traits of antisocial personality disorder, and intelligence.

In sentencing, Stein acknowledged the "extremely moving" victim impact statements from Victoria's devastated mother, brother, sister, daughters, partner and former husband.

"They spoke of their deep grief, anguish and bewilderment at your actions," she said.

"Your actions have inflicted an unimaginable, profound suffering which I cannot adequately capture in a few short sentences.

"Your conduct remains unfathomable and unimaginable."

Neumann was staring at the floor as he learnt his fate on Wednesday.

He was sentenced to 27 years behind bars. This was reduced by 15 per cent for his early guilty plea to 22 years and 11 months non-parole and backdated to his arrest.

Victoria Stewart's family have remembered her as a caring and creative woman. Image: AAP.

Clifford Arthur Neumann's sentencing "was never going to be enough."

Victoria's murder was one of four unrelated deaths across South Australia in a single week, prompting the state government to order a royal commission into family, domestic and sexual violence.

Speaking outside court, Victoria's brother Douglas Jones said his sister was "the best of us".

"She was caring, loved her kids. I am very proud of who she was. I just miss her," he said.

He said he hoped Neumann's sentence set a precedent going forward and stressed violence was never the answer.

Victoria's daughter Tara Songer said the jail term was "never going to be enough".

"No matter how high or low, the pain and suffering that me, my siblings, my family, my mum's friends, even my friends all encountered, it was never going to be enough to justify that pain," she said.

"My mum was the most fantastic woman you could ever meet. She was creative, friendly, kind, funny, would always laugh. I miss her a lot, miss her more every day."

"It doesn't seem like a lot of time when we have to go through a whole lifetime of it," Dogulas added.

-with AAP

Feature image: AAP.