Heartbreaking act by murdered girl's family

Ms Manno's mother Aggie Di Mauro held the urn tightly by her side as she heard the "devastating" sentence. Luay Sako, 39, would serve a 36 year sentence and be eligible for parole after 30 years.

Outside court Ms Di Mauro said Sako deserved a life prison sentence for the stalking and murder of her daughter.

The 23-year-old was asleep in her bed in Melbourne's northeast on November 16, 2020 when Sako smashed through her bedroom window and stabbed her 23 times.

"The court decided to grant him mercy even though he showed Celeste none," Ms Di Mauro said outside court.

"Quite clearly, his right to mercy was more important than her right to life."

The court was told Ms Manno and Sako were briefly co-workers but he began harassing and stalking her after she turned him down romantically.

Over a 12-month period, Sako sent her more than 140 messages from a number of Instagram accounts, with the communication becoming increasingly vulgar and degrading.

Ms Manno went to police to get an intervention order against Sako but his contact only stopped after he was charged with breaching the order.

The day after he was arrested Sako bought the knife he would use to kill Ms Manno three months later, prosecutor Patrick Bourke said.

Sako used Instagram and Google Earth to find Ms Manno's home and drove past the property at least three times.

He found the home's floor plan online and used it to pinpoint her bedroom.

On the night before her death, Ms Manno posted a photo of her boyfriend for the first time on Instagram.

A few hours later, Sako broke into her bedroom while she was sleeping and killed her.

Justice Dixon said the Instagram photo was the "final trigger" for an obsessed and jealous Sako and the 39-year-old carried out the killing with "chilling efficiency".

"Celeste deserved life but you decided otherwise," Justice Dixon said.

In sentencing, the justice took into account Sako's diagnosed severe personality disorder, major depressive disorder and body dysmorphic disorder.

She said the conditions impaired his mental function but he was still able to understand the crimes he was committing.

A psychiatrist told the court Sako's prospects of rehabilitation were limited because he needed intensive treatment that was not available in the prison system.

But Justice Dixon said she was not persuaded that wouldn't change and his condition would remain untreatable.

She noted while the murder of Ms Manno was a grave example of a grave offence, it did not warrant a sentence of life in prison.

Ms Manno's family dropped their heads and started crying in the courtroom as the sentence was handed down.

With Australian Associated Press