"I killed her." After stabbing his wife, Shahab Ahmed calmly called triple zero.

In February 2017, Shahab Ahmed dialled triple zero.

“What happened to your wife there tonight?” the operator asks.

“I killed her,” Ahmed calmly replies.

“How did you do that?” he’s asked.

“With knife,” he says.

Police were on the doorstep of the Sydney unit within minutes and found 29-year-old Khondkar Fariha Elahi dead in the couple’s bedroom.

She’d been stabbed 14 times.

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However despite that emergency call confession, the Bangladeshi born Australian resident has pleaded not guilty to murder, claiming partial defence of substantial impairment by abnormality of the mind.

Prosecutors have rejected a guilty plea to manslaughter.

Ahmed told police in an interview on the night, he and his wife had argued after he discovered she’d been having an affair.

The court heard, he smoked two cigarettes, posted “the end” on Facebook, and updated his wife’s profile photo to a smiling shot of them both.

Then, he called police.

“She was breathing for some time, then I called you guys,” Ahmed told police, before admitting he hadn’t checked on her between the stabbing and calling Triple-0.

The prosecution and defence both agree the stabbing came immediately after the couple argued about Ms Ehali’s secret affair with friend Omar Khan.

Ahmed snatched his wife’s phone, demanded access to read her phone messages and threatened to kill her while holding a kitchen knife.

“I will show that you are lying. After proving that I will go away,” he said.

After being granted access and seeing her ongoing contact with Mr Khan – including messages of a sexual nature – Ahmed began stabbing Ms Elahi repeatedly.

Prosecutors allege Ahmed turned his mind to murder in 2016, when searching the web for “how should cheating be treated” and other terms.

“What is the punishment when wife cheat with husband”, “what’s the best punishment for married man caught cheating on their wives” and “marriage advice” (sic) were among other queries he made in December 2016.

The judge-alone trial will resume on Tuesday.

With AAP