While Jay held his baby as she took her final breaths, a stranger tried to blackmail him.

As Melbourne couple, Jay and Dee Windross, steeled themselves to say goodbye to their terminally ill baby girl in April, messages started pouring in from an unfamiliar number.

A woman had found the phone Dee had left in a public toilet at Chadstone Shopping Centre three days earlier; the phone holding precious pictures of their 11-month-old Amiyah, who had been born with an undiagnosed neurological condition and was then taking her final breaths.

The stranger offered to deliver the device to their Beronia home, but only if $1000 was transferred into her bank account. If they refused to pay up, she threatened to delete the photos or sell the phone.

Yet, as it was later discovered, the woman never had it in the first place.

Malaysian national, Siti Nurhidayah Kamal, faced County Court on Thursday, having earlier pleaded guilty to blackmail over her attempts to scam the couple.

The 25-year-old mother of two had contacted Jay on April 23, after seeing a Facebook post in which he appealed for the return of his wife's stolen phone.

Using the information provided, she pretended to have found it and demanded funds for its safe return.

Despite being told of Amiyah's condition and eventual death the following day, Siti continued badgering the grieving father with threatening messages.

According to The Age, just hours after the little girl died in her parents' arms, Siti wrote, “Yes I will keep the phone and return to you once you have cash deposit me money. please forgive me I never meant to this to your family. im really sorry.”

In total, 158 communications were recorded between them, in which Siti became increasingly desperate: “are you going to deposit or not? please I don’t want to talk. I feel like I want to cry,” she reportedly wrote in one of her final messages.

But no payment was made, and Siti was arrested at a Springvale boarding house two days later.

"You are a predator."

In a statement read during Thursday's hearing in the County Court, Jay described the woman as "a predator".

"You, a mother yourself, devised a plan to extort money from a family that was already at their lowest point they could possibly be in their lives," he said.

"You took moments away from the last opportunity I could have with my breathing daughter to negotiate and threaten me with a phone you never had.

"I don't think there is a word in the English dictionary that describes you as a person. You are a predator."

Siti, who has two children in Malaysia, has been in police custody since her April arrest.

She and her husband arrived in Australia on a bridging visa in September last year, and the court heard that she had struggled to make ends meet as a food delivery rider.

Her lawyer, Rahmin de Krester, conceded that her crime was "entirely opportunistic and said that her guilty plea indicated her remorse.

"She's done the wrong thing," he said. "It was a cruel and criminal hoax that took advantage of these people when they were at their lowest."

Siti Nurhidayah Kamal was remanded until February pending a further psychiatric report and will be sentenced at a later date. The maximum penalty for blackmail is 15 years behind bars.

The phone has never been found.

With AAP.