According to police, Moutahir stopped on the steel cable and was suspended in the air for several seconds.
Police claim she likely then “began to struggle” after realising she had stopped.
“This led to her becoming unbalanced and she fell from the harness around 20m into the forest below and was killed instantly,” a police spokesperson said.
“It’s also possible she had some sort of panic attack and that’s what made her struggle or maybe some other medical episode but we are waiting for the post-mortem results.”
An investigation has since been opened up into the fatal accident with officials examining the footage taken by the two girls.
Authorities will carry out checks of the safety equipment and, as a precaution, have temporarily closed the park while the investigation is carried out.
“The investigation will be looking into whether the woman was attached correctly and secured properly to the zipline cradle,” a source told local media.
“Maintenance records will also be examined and the whole structure will be checked to ensure full safety regulations were being adhered to, so consequently it will remain closed.”
Matteo Sanguineti, a director of Fly Emotion, said: “Our first thoughts are with the lady and her family. We still don’t know for certain what happened.
“We are co-operating with the authorities to try to understand what happened. The zipline opened 13 years ago and in that time more than 200,000 people have used it and we have never had any incidents. I am shocked and incredulous.”