Linda Norgrove, from Lewis in the Outer Hebrides, had been working in the country when she was kidnapped.
Former colleagues have told a BBC Alba documentary that her captors told Ms Norgrove she was only being held hostage as a bargaining tool.
The 36-year-old was killed by a US grenade during a failed rescue attempt.
Ms Norgrove had been working on humanitarian projects in Afghanistan in 2010 when she was seized by rebels.
Colleagues still working in the country told BBC Alba that her captors told Ms Norgrove they did not intend to kill her.
She was led to believe she was being held captive to secure the release of rebel prisoners and would be set free when that happened.
The programme also shows images of Ms Norgrove's kidnappers that she took herself on her camera and phone before she was killed.
It had first been thought her captors killed her during the US rescue mission in October 2010 but later evidence confirmed she was killed by a grenade thrown by a US special forces soldier.
Ms Norgrove was abducted along with at least one other colleague who survived the rescue attempt.
Abdul Wadood, another former colleague who is still working on humanitarian projects in Afghanistan, said: "Linda asked the abductors when they were planning to kill her and then the abductors talked to her in a very soft language and they told her and assured her that she would not be killed, because that was not their purpose to kill her - all they wanted was to release some of their prisoners, in the end she would be released when this deed is done."
Travelling to Afghanistan, Ms Norgrove's parents John and Lorna said it was important for them to see where their daughter had lived and worked and to review the aid work now supported by the charity they set up in her name.
Mr Norgrove said: "We deliberately took a choice that we thought what we should try and do is try and make something positive, because I think that's what Linda would have wanted after Linda had been killed.
"It was with that in mind that we started up the charity that we did and it stopped us getting totally involved in all this blame culture of trying to work out whose fault it was, because at the end of the day I don't think it was anybody's fault."
The Linda Norgrove Foundation is now providing financial help for the kind of work Ms Norgrove did while she was in Afghanistan, including support for schools and hospitals.
Lorgan Linda - Linda's Story will be on BBC Alba on Monday 8 October at 21.00 and later on the iPlayer
The aid worker who died in Afghanistan during an attempt to free her two years ago was told by her captors they were not going to kill her, it has emerged.