A white nationalist inspired by the Christchurch massacre searched for bomb-making recipes and detonated three makeshift explosive devices in preparation for his own terrorist attack, a court has heard.
Brothers Joshua and Benjamin Lucas are charged with preparing or planning for a terrorist act, with Joshua Lucas also charged with intentionally advocating for others to do a terrorist act.
The pair - now aged 23 and 25 - were arrested in March 2020, ending what prosecutors allege was a year of plotting, and both have pleaded not guilty to the charges.
No specific time, place, target or method was finally decided upon by the brothers, the crown prosecutor said when outlining his case in the NSW Supreme Court in Parramatta on Tuesday.
However, the court would see or hear a considerable body of evidence - including internet searches, social media posts and purchases of various items or pieces of equipment - to support the allegations their plans were well underway, he said.
The pair had decided Joshua Lucas would ultimately be the one to carry out the attack, and he had searched for potential targets, including mosques in Wollongong, synagogues on the NSW south coast, and a defence facility near Jervis Bay.
The pair also travelled to Sydney airport and took photos of the perimeter fence.
"(This) is further evidence of researching ... reconnaissance if you like, of potential terrorist targets," prosecutor Chris O'Donnell said.
The court also heard Joshua Lucas had researched recipes for bombs and pipe hand grenades, and had constructed and detonated three devices to test out methods - taking pictures and filming various parts of the process.
"In two of these photos, it's alleged Benjamin Lucas is pictured smiling ... with his head next to the improvised explosive device," Mr O'Donnell said.
He was at two of the detonations in July 2019, and the court would hear evidence from former associates of the accused who were also present, Mr O'Donnell said.
There are also extensive digital communications over the year, in which Joshua Lucas spoke about shooting up mosques, mowing down Chinese people and killing Aboriginal Australians.
"I'm not a psychopath, but yes, I support and promote terrorism," Joshua Lucas allegedly wrote, in one Telegram message from February 2020 read out to the court.
Both men subscribed to neo-nazi ideology, and idolised the Christchurch terrorist, a gunman who shot dead 51 Muslim worshippers in March 2019, Mr O'Donnell said.
"He is an Australian hero," Joshua Lucas allegedly wrote in one message read to the court.
"What he did was perfect, massacred Muslim dogs - 50 (of them).
"I'll massacre 100 more Muslim dogs."
In other messages Joshua Lucas discussed what type of shrapnel would cause the most damage to human bodies, and he encouraged others to act out their terrorist dreams.
"Turn that hate into motivation to commit terrorism," he told one user.
In another chat room, he told his peers to "bomb your local mosque".
In other messages he said he wouldn't be surprised if he "got raided" and at one point suggested he was on a counterterrorism watchlist.
A week later - on March 14, 2020 - he was arrested, and his home searched.
Police allegedly found a machete, six gel blaster guns, ammunition, packets of ball bearings, a balaclava and a Eureka flag.
When officers searched Benjamin Lucas' home a day later, they allegedly located another gel blaster gun and a heavily damaged desktop computer, which he admitted to police he had smashed with a brick after panicking upon his brother's arrest.
The trial continues.
