A 22-year-old man will face court after he was charged in relation to the murder police accountant Curtis Cheng in Sydney's west last month.
Police from the Joint Counter Terrorism Team and the Middle Eastern Organised Crime Squad arrested the man on Watts Road at Ryde shortly after 2pm Friday.
The Marsfield resident was taken to Ryde Police Station and charged with participating in a criminal group.
He was refused police bail and will front Parramatta Bail Court on Saturday.
Cheng was shot dead outside Parramatta police headquarters in an attack that shocked the nation.
The 15-year-old killer was shot dead by police at the scene.
On Friday, Sydney man Talal Alameddine, who allegedly gave the teenager the firearm used in the killing, was refused bail after being called a "great threat to the community".
Cheng, a 58-year-old police accountant, was gunned down in an attack police think was linked to terrorism.
He was remembered by friends and family as a kind and gentle father who was dedicated to his work and family.