The woman charged with the murder of her six-month-old son had a disturbed mind at the time, but whether the defence of infanticide is available to her is 'a question for the jury”.

That's according to Dr Jeremy Skipworth​, University of Auckland senior lecturer and 20-year forensic psychology veteran.

Skipworth was giving evidence at day three of the trial of Melody Ngawhika​ at the High Court in Rotorua on Wednesday.

Ngawhika faces one charge, that between August 28-29 last year when the country was in a Covid lockdown, she murdered her six-month-old son Elijah-Abraham Ngawhika.

Both Crown prosecutor Amanda Gordon and defence lawyer Fraser Wood told the jury earlier that there was no dispute Ngawhika killed her son by suffocating him.

The key issue, both said, was whether she murdered her son or whether she had committed infanticide.

According to the Crimes Act 1961, the rare charge of infanticide can apply 'Where a woman causes the death of any child of hers under the age of 10 years in a manner that amounts to culpable homicide, and where at the time of the offence the balance of her mind was disturbed”.

Skipworth outlined the history of abuse suffered by Ngawhika, and earlier diagnosis and treatment for mental health issues, and told the jury he believed she was indeed undergoing a major mental disorder at the time of the killing.

He said there was 'no real issue” that Ngawhika 'had a disturbed mind”.

He said the difficulty with an infanticide charge was it required the mental disturbance to be as a direct result of childbirth.

'It's questionable whether there is a significant connection to childbirth,” he said.

'But there may be an argument. . . it's a question for the jury.”

He also referred to a video shown to the jury on Tuesday of Ngawhika's police interview, referring to a comment she made about auctioning her daughter online, and when she ripped up a piece of paper on which she'd been asked to draw a map of her home.

'A couple of pretty clear episodes of unusual paranoia.”

He also said that during their two-hour interview, she spent more than half that time 'sobbing, crying uncontrollably”.

The jury was also told details of a phone conversation between Ngawhika and Elijah's father, when she called to tell him she had suffocated their son.

'My paranoia got the best of me,” she told him.

'A voice in my head told me to do it.”

The trial is set to continue.

-Benn Bathgate/Stuff.