Ms Sutton had been studying at Canberra's ANU Centre for Arab and Islamic Studies and was acting director of the London-based Institute for War and Peace Reporting.

She was found dead at Istanbul's Ataturk airport overnight on October 17-18 after flying from London, en route to Iraq's Kurdish region. Initial reports indicated the 50-year-old had taken her own life, but family and friends in Canberra and overseas were suspicious about the circumstances.

A statement issued by Ms Sutton's family on Friday said they were now satisfied that she acted alone in her death.

Her sister Jenny Sutton said the preliminary conclusion was based on an extensive review of information provided by officials on the ground.

"The family is satisfied with the investigation undertaken by the Turkish authorities.

"We were deeply sceptical about initial reports. But based on the evidence we have seen, at this stage we believe that Jacky acted alone."

Jenny Sutton said the Turkish authorities had cooperated fully since her sister was found, providing access to a complete dossier of available evidence, including copies of airport security camera footage and all relevant documentation.

The statement said there remained the possibility that additional information would come to light.

The family and the institute will seek "a further assessment from an independent investigative expert in order to confirm the findings once the Turkish investigation is complete."

They were satisfied all security footage had been provided without apparent time gaps. Other information included still photographs, witness statements, a viewing of Ms Sutton's body and a site visit by institute staff.

There was nothing to indicate any struggle or that anyone else was present when Ms Sutton died. She had two credit cards and a large amount of cash with her and there was no sign of theft.

Ms Sutton's family asked for privacy and said a further statement would be made later.

Opposition foreign affairs spokeswoman Tanya Plibersek offered condolences to her family and friends, "and the broader community of advocates to which she belonged."

"The solidarity she showed for women at the front line of conflict zones, is the solidarity we return to her with our own thoughts today," Ms Plibersek said.

Ms Sutton had worked for the BBC World Service between 1998 and 2000, reporting from Africa, the Middle East and London. She also worked fo rVatican Radio and contributed to the ABC website The Drum.

Her research focused on international development support to female media professionals in Iraq and Afghanistan between 2003 and 2013. Ms Sutton advised the UN heritage and education organisation UNESCO, and worked in Canada and Eritrea, where she helped start an English language newspaper.

ANU offered staff and students counselling after her death. She had tutored more than 130 students.

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