Briton Jacky Sutton, 50, was found dead in a restroom Saturday night at Ataturk Airport's international transit terminal. She had failed to board a connecting flight to Irbil, Iraq, where she was based for her work with the Institute for War and Peace Reporting,
a London-based group that trains local journalists in conflict zones.
Friends and colleagues were skeptical of initial reports from Turkey's state-sponsored Anadolu news agency, citing Turkish security officials, that Sutton hanged herself, and they called for a full investigation into her death.
Turkish authorities have not responded to CNN requests for comment.
But having met with Turkish authorities investigating her death, her family and the Institute for War and Peace Reporting issued a statement
saying they had "reached the preliminary conclusion that no other parties were involved in her death."
"The family is satisfied with the investigation undertaken by the Turkish authorities," said Jenny Sutton, Jacky's sister.
"We were deeply skeptical about initial reports. But based on the evidence we have seen, at this stage we believe that Jacky acted alone."
The statement said that Turkish authorities had shown the family the full dossier of evidence relating to the case, including unedited closed-circuit TV footage, still photographs and witness statements.
Jenny Sutton viewed her sister's body, and family members and the institute's staff visited the airport.
Jacky Sutton was found with two credit cards and a significant amount of cash on her, and there was no suggestion any of her belongings had been taken, the statement said.
All evidence indicated that Sutton had been alone, and there was no sign of a struggle, it said.
The statement said Sutton's family and employer would seek an independent expert assessment of the Turkish investigation once it was completed, and remained open to the possibility more information could surface.
It requested the Sutton family's privacy be respected.