Teenager pleads guilty to murder of Jack Westren at NSW train station

A 16-year-old boy has pleaded guilty to murder after stabbing a man with a brain injury at a train station on the NSW South Coast.

Port Kembla Children's Court heard the teenager brought a hunting knife to Shellharbour Junction train station on January 28 last year, where he fatally stabbed 25-year-old Jack Westren in the heart and abdomen.

A group of minors lured Mr Westren to the site over social media with plans to violently ambush him.

Today’s guilty plea came two weeks after four boys and one girl, aged between 13 and 15, pleaded guilty to manslaughter over their roles in the killing.

They legally cannot be named due to being minors.

The sole adult charged over the incident, 39-year-old Tamara Doust, has pleaded not guilty to murder over her alleged role in the incident.

Boy posed as girl to lure victim

Court documents state one of the 13-year-old boys involved in the attack began messaging Mr Westren on social media the night before the attack, posing as a 12-year-old girl named "Amy".

He encouraged Mr Westren to meet up at Shellharbour Junction train station and told him throughout the night "I want you" and "I like older boys".

The documents state Mr Westren sustained a traumatic brain injury in a motor vehicle accident in 2008, with his medical issues and behavioural disorders manifesting in various ways, including being "immature" in his approach to relationships.

He would frequently communicate with younger girls on social media, with his intellectual functioning previously assessed by medical professionals to be in the "extremely low" range.

The boy posing as Amy shared screenshots of the messages he exchanged with Mr Westren in a group chat.

Court documents included a message posted in the group chat which read: "There's a paedophile that we're trying to get to come to Shelly tomorrow, youse want to bash him?"

Video taken that night showed some of the boys in a front yard, wearing balaclavas and "simulating assaults, kidnapping and robberies with weapons".

The next day Mr Westren asked "Amy" what train she was going to catch to Shellharbour.

The boy and three friends, including a 15-year-old girl who would act as "bait", boarded a train to meet him while the boy continued to exchange messages with Mr Westren.

That group met up with others who were allegedly driven to a nearby mall by Ms Doust before the attack.

The boy who pleaded guilty to murder sent video messages to other friends on Snapchat which depict him saying "we're setting him up" and "it's fun shit".

Ms Doust then allegedly took 11 teenagers to the train station, six of whom travelled in the boot of the vehicle, with some carrying knuckledusters and the knife.

The 15-year-old girl who was being used as "bait" approached Mr Westren, who was waiting at the train station at the agreed time.

The group then ran towards him, with the boy who pleaded guilty to murder carrying a hunting knife and wearing a T-shirt over his face.

Ms Doust is accused of throwing the first punch that caused Mr Westren to fall to the ground, where the group then repeatedly assaulted him, before the boy stabbed him in the abdomen.

They all fled from the scene, with court documents stating the boy stared out of the car window and said several times, "Why did I stab him?"

People nearby ran to Mr Westren's aid and administered CPR until an ambulance arrived, but he died at the scene.

After Ms Doust was arrested at her Albion Park Rail home, she allegedly took police to a creek bed where the hunting knife was buried.

The five teenagers who pleaded guilty to manslaughter are all on bail and will receive their sentence date this month.

The boy who pleaded guilty to murder will receive his sentence date on September 4, while a trial date will be determined for Ms Doust at Sydney's Supreme Court on the same date.