A Sydney man wanted by the FBI over accusations he helped young Americans join Islamic State has confessed to Turkish authorities that he worked for the group as a translator and communications official, the ABC can reveal.

Key points: A four-year manhunt for an Islamic State-linked Australian has ended after Mohamed Zuhbi was captured in Syria

A four-year manhunt for an Islamic State-linked Australian has ended after Mohamed Zuhbi was captured in Syria The FBI alleges Zuhbi helped US citizens to join Islamic State and wants him extradited to America for trial

The FBI alleges Zuhbi helped US citizens to join Islamic State and wants him extradited to America for trial Zubhi's father told the ABC his son was merely conducting aid work in Syria

Mohamed Zuhbi, 29, was captured by a pro-Turkish militia in June last year and handed over to Turkish authorities.

He has since been convicted in a court there and is expected to be deported to Australia soon.

Zuhbi was one of the most prominent among Australia's Islamic State supporters and was close to many of the Australian men who went to fight and die in Syria and Iraq with the declared terrorist group.

Until now there has been no suggestion that Zuhbi actually joined or fought for Islamic State.

However, the ABC has obtained Turkish court documents which state the Australian confessed that he had travelled to the group's de-facto Syrian capital, Raqqa, in 2015, to join, and underwent weeks of religious and military training.

He told prosecutors he was then assigned a role in an Islamic State bureaucracy connected to travel and communication and also worked as an English translator for the group.

When Raqqa fell to a Kurdish offensive in mid-2017 he used smugglers to flee to Syria's north-west.

He then lived in that area for two years — even opening a childcare centre with a male relative of a local woman he married — before being captured at a militia checkpoint, the Turkish documents state.

He was sent to Turkey and ultimately sentenced to more than seven years for joining Islamic State and related crimes, the documents states.

The court then gave him a series of reductions because of "assistance provided" that saw his final sentence reduced to about a-year-and-a-half.

The Turkish documents are authentic and base themselves on what they say is Zuhbi's own confession.

However, the Turkish judicial system has become increasingly controlled by President Recep Tayyip Erdogan's authoritarian government and convictions and confessions there would likely not meet the levels of evidence required in the Australian judicial system.

After Zuhbi left Australia in 2013, he began posting online about doing aid work in Syria. ( Supplied )

His arrest and expected return to Australia is the end of a four-year manhunt by authorities for the Australian citizen but may also create a new legal headache for the Federal Government.

The US has explicitly stated it expects Zuhbi to be extradited to America for trial there, with prosecutors in Houston arguing that because Zuhbi was engaged in an alleged conspiracy with US citizens they have jurisdiction.

However, Zuhbi is an Australian citizen and given his apparent confession in Turkey, the Australian Government may wish to first prosecute him here for his ISIS membership.

He has also been accused in the media of helping Australians cross into Syria and may face charges related to those Australian allegations when he returns.

The Australian Government declined to respond to questions by the ABC about whether Zuhbi would face Australian courts or if Canberra would allow the Americans to prosecute him.

'He's not a criminal'

Zuhbi's father, Bara Zuhbi, spoke to the ABC from the family home in Sydney's south-west earlier this week.

He said his son was born in Syria and had travelled there to help those affected by the war.

"I don't want him to go to [the US]," he said.

"I don't want the Americans to touch him; he didn't do anything — he's not a criminal — and it's none of their bloody business."

Zuhbi did not join Islamic State or fight for them, he said.

If his son was accused of crimes, he said the family should be informed of them, and Zuhbi should be tried in Australia.

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"This is not right … this is an Australian citizen? We think he has done something wrong? [If] we got him back, we take him to court and the onus is on us to prove he's done something wrong to Australia or any Australian citizen.

"If he didn't do anything wrong, he should be let go."

He speaks to his son every week and said Zuhbi was unaware of plans to return him to Australia or charge him with crimes here.

The Australian Federal Police referred the ABC's questions to the Department of Home Affairs, who declined to comment on Zuhbi's case.

Zuhbi has been previously linked in the press with helping three Australians — John Zakhariev, Sharky Jama and Yusuf Yusuf — and two Americans travel to Syria.

The ABC is unable to verify his role facilitating the travel of the Australians, but Zuhbi has been indicted in the US District Court over the case of the two Americans, Houston men Asher Abid Khan and Sixto Ramiro Garcia.

FBI alleges Zuhbi is an Islamic State facilitator

Mohamed Zuhbi has now been detained by Turkish authorities ( Supplied )

In 2015, the FBI charged Asher Abid Khan, from Houston, with conspiring to provide material support to Islamic State and to kill people overseas. The charges related to an alleged 2014 plan hatched by him and Garcia to travel to Syria to join the group.

In material filed with the US District Court between 2015 and this year, prosecutors outlined their allegations, as described below.

A key element was that Khan and Garcia had an "Unnamed Co-Conspirator" — identified only as "CC-1" — who played a central role in facilitating their plan to join Islamic State.

Prosecutors later identified CC-1 as Zuhbi. In March 2016, they announced they had also charged him with providing material support to Islamic State and conspiring to kill people overseas.

"[Zuhbi] is a foreign national, believed to reside in Turkey, who facilitates the travel to Syria of foreign fighters seeking to join [Islamic State]," a prosecution document states.

'I wanna join ISIS can you help?'

Asher Abid Khan was raised in Houston but moved to Sydney in October 2013 after graduating from high school.

In January 2014, while still in Sydney, he used Facebook to reach out to Zuhbi, who by that point was living in Turkey and Syria.

"I wanna join ISIS can you help?" Khan said, according to court documents.

Facebook posts under Mohamed Zuhbi's adopted name. ( Supplied )

Zuhbi told Khan he could help him if he flew to Istanbul, and then travelled to the Turkish border city of Antakya, where he would be waiting for him.

The next month Khan and Garcia flew to Istanbul but Khan's family managed to convince him to return to the US.

Garcia, however, was undeterred — he travelled to Antakya and met with Zuhbi.

Later that day he sent a message to Khan saying he had "been delivered :)" and that he was still with "Mohammad," whom prosecution documents state was Zuhbi.

Later that year Garcia message Khan to say he had finally made it to "ISIS."

In December, a message was posted on Facebook announcing Garcia had died in the fighting.

Khan was arrested by the FBI several months later and then, in March 2016, the US issued a warrant for Zuhbi's arrest.

"By providing additional personnel to serve as fighters in [Islamic State]'s ranks, Zuhbi directly contributed to and supported all aspects of the organisation's mission, thereby engaging in criminal activity that harmed the interests of the United States and threatened its security," prosecutors stated in a document filed to the court in April 2016.

The US Department of Justice and the FBI both declined to discuss Zuhbi's case.

Bara Zuhbi says his son states the US charges are "false and exaggerated."

"[Mohamed said to me], 'This is all wrong. It's all false. I did speak to one person, a Pakistani or something … And it was about him wanting to cross.

"He didn't give me details, but he said this was one person. [Zuhbi said], 'I wasn't in the business of greeting people'."

If Zuhbi returns to Australia, he will be the second Australian returned home from the Middle East, following a decision by the Turkish Government late last year to begin deporting almost 1,000 people they accuse of being Islamic State members or associates, and their relatives.

Agim Ajazi was extradited to Queensland on terror charges in December 2019. ( ABC News )

The first Australian returned from Turkey as part of those deportations, 30-year-old Queensland man Agim Ajazi, arrived in Australia in early December.

He has since been charged with entering Syria with the intention of fighting and being a member of a Syrian Al Qaeda affiliate.

Father said Zuhbi was setting up Syrian bakery

Zuhbi left Australia for Syria in 2013, where he adopted the name Mohamed Ibn Albaraa.

He came to the attention of Australian authorities and the public when he released videos showing him delivering aid to Syrians in the north-western area of Lattakia, which borders Turkey.

In August 2016, a home associated with Zuhbi family in Sydney's south-west was raided by federal police over allegations of overseas terrorism financing.

Baraa Zuhbi arriving at the house on the day it was raided by counter-terrorism police in August 2016. ( ABC: Jessica Kidd )

Bara Zuhbi told the ABC his son eventually settled in Syria's north-west, married a local woman, and was trying to set up a bakery. The couple have four young children, and his father is concerned about their fate if Zuhbi is deported to Australia.

In May 2018, Zuhbi was captured by Kurdish forces and held for six months before being released, his father said.

Then, in June 2019, he was detained for a second time by a Turkish-backed militia, the Sultan Murad Division, at a checkpoint in or near the northern Syrian city of Efrin, where he had gone to buy cooking equipment.

The militia held him for three months before sending him to Turkey where he faced a brief trial, his father said.

Zuhbi told audience he was supportive of Islamic State

An ask.fm page where a person using Zuhbi's adopted name answers questions around travel to Syria. ( Suppied )

In May 2014, a person using Zuhbi's adopted name and linked to his Facebook page hosted a question and answer session about travelling to Syria on the website ask.fm.

In answer to a question about how to avoid the risk of being refused entry to Syria, the person said: "If you try and enter legit border crossings, you will likely get sent back, but if you get smuggled in, like most, you will not have any issues."

The ABC interviewed Zuhbi in late June 2014 — the same month Mosul fell to Islamic State and the group declared its global caliphate.

In that interview, Zuhbi said he had received more than $30,000 in donations before his bank account was shut down by the Australian Government.

"We look after the injured, the orphans and the widows … we also sponsor bakeries, we've sponsored ambulances like for patient transport," he said.

He rejected suggestions he was providing financial assistance to Islamic State or other terrorist groups.

"Funding for jihad and so on and so forth, it doesn't come in amounts of $100, $20, $50 and so on — it comes in amounts of 100,000, 50,000, 200,000," he told the ABC.

Mohamed Zuhbi has been the subject of a four-year international manhunt. ( Supplied )

The ABC asked him if he was working as a middleman to help people enter Syria.

"The only thing I've helped with is charity work, I haven't helped with anything else," he said.

"Where's the proof if they want to accuse anyone of doing that?"

He attracted so much attention he also appeared live from Turkey during an episode of the SBS panel show, Insight.

"Look, I'm not, I'm not a part of any particular group but I'm most vocal, vocally supportive of the Islamic State," he told the audience.

"I believe that they are the future of Syria and I believe that they're the future of the Islamic empire to come.

"I have full conviction that at the rate that they're going, they will indeed establish justice and establish the Koran of Islam in the land."

Zuhbi told Insight he was not fighting, but confirmed he was comfortable with other Australian Muslims fighting for Islamic State.

"Look, just as the Israeli Defence Force has Australian members in it, serving, killing innocent children and women … if an Australian citizen wants to fight for ISIS and fight the oppressors like the Assad regime, look, this is their personal choice."

At its height, Islamic State controlled an area across Syria and Iraq the size of Britain and governed the lives of up to 12 million people.

It gained global infamy for a well-documented series of war crimes and abuses, including the attempted genocide of Yazidis, killing of prisoners, public executions and floggings, and crimes against women.

The group was officially defeated in Iraq and Syria in March last year by US-backed Syrian Kurdish forces, but it continues to pose a threat to countries in the Middle East, Asia and Africa.