Jason Galleghan death: Kayla Dawson and Richard Sione jailed for decades over vicious assault of teen over AirPods at Doonside

A man and a woman who were involved in the savage beating and murder of a teenager inside a western Sydney house have been jailed for decades.

Jason Galleghan died after being lured to a Doonside home and viciously assaulted on August 4, 2021 in a crime which shocked Sydney.

Kayla Dawson and Richard Sione faced a judge-alone trial in the NSW Supreme Court earlier this year after pleading not guilty to murdering the 16-year-old.

However, Justice Robert Allan Hulme found the pair guilty of murder, finding they were a part of a joint criminal enterprise in which Jason was beaten and left for dead.

He was lured to a home in Doonside, in Sydney's west, on August 4, 2021 before he was attacked by a group of adults and juveniles, the court heard.

At the time, Dawson, a mother of one, had accused Jason of stealing a pair of AirPods, and he was lured to the house as 'retribution', Justice Hulme said in his sentencing remarks on Friday afternoon.

Jason caught a train from Sydenham and when he arrived at the property, he was brought into a bedroom where he was assaulted by Sione and several juveniles, while Dawson recorded the beating.

Most of the people in the house were affected by alcohol and drugs at the time, the court heard.

Justice Hulme said it was 'clear' that the plan was for Jason to be brought to the home and bashed, referring to text messages.

The court heard that Sione punched and kicked Jason while interrogating him about the earphones.

Sione left after about three to five minutes, the court heard, however the assault continued, this time at the hands of several of the juveniles.

During the assault, Jason was stripped down to his underwear.

After the assault finished, Jason was left alone in the house and he was later taken to hospital, where he died two days later.

'Jason was left on the floor of the bedroom while everyone else left the house,' Justice Hulme said.

Justice Hulme described Dawson's delay in calling an ambulance as 'reprehensible' given he was 'helpless' and unable to breath.

Videos of the assault were found on the phones of Dawson, as well as two of the juveniles.

While she did not take part in the beating, she was heard laughing and saying she was sending the recording to 'Johnno'.

During part of the recording, Jason was made to repeat comments about the '27' postcode gang and its rivals.

Dawson had argued that she was not guilty of murder due to her cognitive impairment, however Justice Hulme rejected that contention.

Sione was found guilty of murder because Justice Hulme found that he was a part of the joint criminal enterprise which led to Jason's death as he was involved in the beating.

Justice Hulme took into account a victim impact statement by Jason's mother, Rachel, which was read to the court on Friday, noting her 'grief, pain and loss'.

The court heard that both had been threatened in jail due to the nature of their crime.

The court heard that Dawson blamed herself for Jason's death, saying that he would not have been killed if she had not told people that he had stolen her earphones.

Sione watched the sentencing proceedings via videolink from jail on Friday, sitting in a chair with his head pointed to the ground.

Both Dawson and Sione were facing up to life imprisonment in jail.

Sione was sentenced to 32 years in jail, with a non-parole period of 24 years

Dawson was given a 20-year term, with a non-parole period of 13 years.