I read some spoiler and it says it was her father but something happened and instead of her father remembering what happened, Kiera was the one with the memories intact. Maybe that's why her father dream about when she died ╮( ̄▽ ̄)╭ don't know if it's true though.
I think her grand mother was the other participant! ╮( ̄▽ ̄)╭