A 16-year-old boy charged with terrorism offences in connection with the Wakeley church stabbing allegedly declared he was 'going to kill' in messages about carrying out a plan against non-believers, a court has heard.
The bishop was delivering a live streamed sermon at 7pm when he was stabbed by an assailant who then attacked a priest.
His alleged attacker was charged with a terrorism offence, which was swiftly followed by widespread search warrants and the arrests of five of his alleged associates.
On Tuesday, a 16-year-old faced Parramatta Children's Court after being charged with conspiring to engage in an act in preparation for, or planning, a terrorist act and having a knife in a public place.
Crown prosecutor Chelsea Brain told the court that messages showed the teen had been involved in a conversation about carrying out a plan against 'non believers'.
The teens talked about spending $2000 to buy two or three 'nerf guns' (a weapon-like toy), which the crown alleges was code for 'dirty guns' that were later referred to as a 'shotty'.
'This is serious s***. We're going to kill but we need patience,' the 16-year-old allegedly wrote in a message read to the court.
Ms Brain said the teen had been actively considering 'some act of violence on members of the community' and had demonstrated support for people involved in the church stabbing.
He recently changed his profile photo on social media to a picture of him holding a rifle in front of an Islamic State flag, the court was told.
In another message to a group of teens who had been arrested on unrelated charges, Ms Brain said the 16-year-old had made admissions to the planning.
'We were planning big stuff, bro. It's conspiracy. Conspiracy for a terror attack I think,' he allegedly wrote after his alleged co-conspirators were arrested.
'We were planning something huge here bro, you don't understand. Huge.'
The court heard the communications between the teens in an encrypted group chat began in March.
The 16-year-old and his alleged co-conspirators were planning a terrorist attack of a 'biological nature', according to the prosecution allegations.
Police have arrested multiple associates (one pictured) of the teenager who allegedly stabbed the priest, after officers obtained warrants
Ms Brain argued the teen should not be released on bail because the protection of the community 'is a very live consideration at this time'.
However, the teen's lawyer Greg James KC opined the crown had failed to particularise his client's alleged offences.
'We don't know, even from all the material, even from an analysis of all the text messages sent...what the terrorist act is said to be, how much had actually been agreed upon...or what had been a matter of speculation or conjecture,' he told the court.
'The appropriate course is not to hold the young person in custody while the prosecution sorts out their ducks.'
Mr James said the teen was charged with a 'double preparatory offence' of conspiracy to engage in preparation for a terrorist act.
'It's twice removed from the central concept of a terrorism offence,' he stressed.
The teen's lawyer pointed to his complete lack of criminal record and his 'exemplary' and 'law abiding' history as factors which would give the court comfort when considering bail.
He argued the prosecution's concerns could be mitigated with 'very stringent' bail conditions which would subject the teen to house arrest and forbid him from using an internet-capable device.
A riot broke out at the church (pictured) following the alleged attack, with police conducting counter terrorism raids against those allegedly involved in inciting the violent actions
Magistrate Janet Wahlquist refused to grant the 16-year-old boy bail after finding there were 'sufficient communications' captured in the encrypted chats, which spoke of planning attacks, stash houses, and getting guns and knives.
'He was clearly aware that what he was doing amounted to terrorism. That did not stop him,' she said.
However, the magistrate did grant bail to a 17-year-old boy who was charged with possessing extremist content after the execution of a search warrant linked to the church stabbing.
The court previously heard the teen had allegedly been in possession of instructional videos on how to build an explosive device, videos of beheadings, and imagery linked to IS and Hamas.
Yet the teen's lawyer Ertunç Ozen SC argued there was no evidence his client had viewed the videos and suggested they might have automatically been saved to his phone.
He noted the teen was only charged with having 124 extremist files saved on his phone, not disseminating them.
'Possession of these documents does not equal endorsement,' he said.
'It is not alleged this young person has any ties, links, or affiliations with any terrorist or ideological causes.'
Mr Ozen argued the offence 'falls very much at the lower end' of the 'broad spectrum' of terrorism offences contained in the legislation.
The arrests of the teenagers were made (pictured) over allegations they were planning a terrorist attack against 'non believers'
Ms Brain opposed bail, noting some of the videos were watermarked with the IS symbol and involved the teen's friends committing assaults on members of the public.
She argued the teen represented an 'unacceptable risk' to the public if he was released on bail.
Magistrate Wahlquist agreed the videos were 'very violent' and the videos of the teen's friends suggested a 'closer association' with him than the other content.
However, she noted the teen had spent the last week in isolation while in custody due to the nature of his charges.
The magistrate took his onerous custody into consideration, along with his youth and lack of criminal history.
Both teens will return to court next month.