WHAT WE KNOW ABOUT THE ALLEGED TERROR CONSPIRACY:
* Four Lebanese brothers - three living in Sydney and one from Syria - have now been implicated in the plot
* Khaled Khayat, 49, and Mahmoud Khayat, 32 were arrested in Sydney in July and have been charged with planning or preparing for a terror attack
* Khaled Merhi, 39, was also arrested in the Sydney raids and has been charged with a non-terror related weapons offence
* Abdul Merhi, 50, was arrested but released without charge
WHAT IS ALLEGED?
* Khaled Khayat accompanied his brother Amen Khayat to Sydney's international airport on July 15
* Australian Federal Police say a bomb was hidden in a meat grinder while Lebanese authorities say another device was in a large child's doll
* Australian police say Amen Khayat had "no idea" he would be carrying a bomb but Lebanon's interior minister say he was involved as a would-be suicide bomber
* Khaled Khayat left the airport with the luggage reportedly because it was too heavy and Amen Khayat flew to Abu Dhabi on an uneventful Etihad flight then travelled to Lebanon
* Following the aborted effort the bomb or bombs were disassembled
* The AFP alleges the brothers then started building an "improvised chemical dispersion device" designed to release the highly toxic gas hydrogen sulfide
* Australian authorities receive information about the plot on July 26, then arrest the men after raids three days later
* Khaled Mahmoud Khayat and Mahmoud Khayat next face court on November 14
* Khaled Merhi is due to appear at Sydney's Downing Centre on August 24 on a weapons charge.