The Sydney man accused of handing a gun to the teenage murderer of police accountant Curtis Cheng has pleaded guilty to committing a terrorist act.
Raban Alou, 19, entered the plea in Downing Centre Local Court on Friday, more than a year and a half after Mr Cheng was shot dead by 15-year-old Farhad Jabar outside NSW Police headquarters at Parramatta in October 2015.
Redacted Crown documents allege Alou gave the now-deceased teenager a .38 calibre Smith and Wesson revolver at Parramatta Mosque less than an hour before the murder.
They also detail a conversation with a female associate the day after the attack in which Alou mentioned "beautiful footage".
"It makes me so happy," Alou allegedly said during the conversation,
"See how he drops? Did you see how much fight he had in him?"
The Crown documents tendered to the court allege Jabar and Alou were alone in the female-only section of the mosque for about seven minutes before Alou left on the afternoon of the killing.
It's alleged Jabar then prayed in the mosque's main hall before changing into a black robe called a dishdasha.
On the way out, he looked up at a CCTV camera and held up his right index finger in a salute used by Islamic State militants.
Mr Cheng died instantly after being shot in the back of the head at close range as he left work on October 2.
The Crown alleges Jabar then strode back and forth while yelling "Allahu Akhbar" before being shot dead by NSW police special constables.
A note found in his pocket talked about "unbelievers" and proved the killing had been a "religiously inspired act of violence in support of IS", the papers allege.
"Know your weapons are nothing compared to what we have," the note allegedly said.
"Know that you all are being watched 24/7."
Three other men, who are all accused of supporting Islamic State ideologies, have been charged in relation to the killing.
The gun used to kill Mr Cheng was allegedly delivered to Alou and a co-accused at a western Sydney park by another man riding a bicycle.
Alou is due to next appear in the Supreme Court on July 7.