Abdul Merhi, 50, Khaled Merhi's brother, who was also arrested, walked from police custody without charge on Tuesday night.
Three men remain in Australian Federal Police custody after the AFP was granted the power to hold them for up to seven days, which expires on Sunday evening.
Police have said they believe the suspects were inspired by the Islamic State militant group.
There may be huge queues of eager travelers waiting to get through the new lengthy security measures Sydney Airport but it seems one Australian airline didn't get the memo.
"There's a lot of stress associated there, and not knowing, and he was shocked that he was being questioned", Kheir said.
Sterling Shepard Injury Status: How Serious Is the Giants WR's Ankle Injury?
He was slated to do a lot of work out of the slot with Marshall and Beckham playing on the outside as targets for Eli Manning . He finished his OU career as the No. 2 receiver in program history, totaling 3,482 yards on 233 receptions.
But Sydney Airport's plan takes that further, linking the same facial recognition system with every other touchpoint throughout the terminal, including baggage drop, admission to the security screening queues, clearing passport control without a passport, completing duty-free purchases and even entering airline lounges document-free.
The United Arab Emirates' national airline said it is working with Australian police in the ongoing investigation, suggesting one of its planes may have been targeted in the plot.
Speaking on the ABC, Justice Minister Michael Keenan had denied there's a heightened security risk due to the larger number of people arriving at airports at a specific time.
Officials have refused to comment on media reports that the plot was to hide explosives or chemicals that would emit toxic gas inside a piece of kitchen equipment.
Mr Turnbull said he would not comment on the alleged terrorist plot, but that Australian Federal Police commissioner Andrew Colvin assured him charges are likely to be laid. "We want to review all the information police had and what basis they had to do what they did".
Police have been gathering evidence since conducting raids at the weekend in what PM Malcolm Turnbull called a "major counter-terrorism operation". At the moment they are employed by subcontractors and don't have to be screened, " Mr Butt said.
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