The man believed to be responsible for helping the terrorists behind last month's Paris attacks enter and leave Syria for training has been personally involved in moving Australian Islamic State recruits into the conflict zone.
Western intelligence agencies have evidence that Tarad Mohammad Aljarba, a 36-year-old Saudi Arabian also known as Abu-Muhammad al-Shimali, was appointed "border emir" and facilitated the entry of several Australian, European and other Middle Eastern recruits into Syria from Turkey throughout last year.
As of mid-2014, he was also Islamic State's "leader for operations outside Syria and Iraq", according to US agencies and the UN Security Council, which placed economic and arms sanctions against him just weeks before the   November 13 Paris attacks. 
It is unclear who the Australians he helped to join Islamic State are, but it remains possible that Aljarba also had the ability to help them leave the conflict zone.
Although authorities now believe the number of Australians currently involved in the fighting has fallen to 110, it is understood that agencies cannot be confident that they know the identities of every foreign fighter in Syria and Iraq, because of the complexities of the conflict and the difficulties in receiving accurate information from terrorist-held areas.
Shortly after the Paris attacks left 130 dead, Aljarba was named as the man likely to have helped its Belgian-Moroccan organiser Abdelhamid Abaaoud enter Syria, and possibly helped five others leave the conflict zone to become suicide bombers. Abaaoud was killed in a raid in Paris days after the attack.
On   November 19, the US State Department announced a $US5 million bounty for information about Aljarba's current location, describing him as having a relationship with Islamic State and its predecessors that dates back to 2005.
"He now serves as a key leader in ISIL's immigration and logistics committee, and is responsible for facilitating the travel of foreign terrorist fighters primarily through Gaziantep, Turkey, and onward to the ISIL-controlled border town of Jarabulus, Syria," the State Department said in an accompanying statement.
"Al-Shimali and the immigration and logistics committee co-ordinate smuggling activities, financial transfers, and the movement of logistics into Syria and Iraq from Europe, North Africa and the Arabian Peninsula.
"In 2014, al-Shimali facilitated the travel from Turkey to Syria of prospective ISIL fighters from Australia, Europe, and the Middle East, and managed ISIL's processing centre for new recruits in Azaz, Syria." Australian authorities yesterday refused to discuss Aljarba and the Australians he helped to join Islamic State.
As of   May, fewer than half of the Australians in the conflict have had their passports cancelled. ASIO director-general of security Duncan Lewis told a Senate estimates hearing at the time that 67 of the 115 passports cancelled at the agency's request involved people in Australia.
ASIO declined to provide updated figures on the number of fighters with cancelled passports yesterday, other than to say that, in total, more than 150 Australian passports have been cancelled or refused in relation to the conflict.
As reported in The Australian earlier this year, Australia's top Islamic State recruiter and terror-plot instigator, former Melbourne man Neil Prakash, did not have his passport cancelled until four months after he appeared in a propaganda video released by the group in   June last year.
In a brief statement, ASIO said the number of Australians believed to have been killed in the conflict had risen slightly from an estimated 40-43 as of   September. "At least 44 Australians are believed to have been killed as a result of their involvement in the conflict," the agency said.The Australian last week revealed Australians were dying at a faster rate than they were being replaced in the conflict.