the living vs the dead

Last month, my sister's friend, an eighteen-year-old high school senior, committed suicide by hanging herself off of a bridge in her back yard. Before she died, she text messaged a friend some cryptic words and the friend, who did not know the girl's intentions, told the girl's parents. Her dad went down to the creek behind her house and saw her body. He tried to recessitate her, but her "knot intrinsicate" had come undone.
The real tragedy of such a hasty exit of the world, especially in the circumstances of this family, was the pain she left behind for all of her friends and her parents (who were only blessed with with one child).
After the initial shock of her friend's departure, my sister became very angry. The only thing I could think of to console my sister was that this girl - an honors student, and a legal adult - while desperate was not ignorant. She was very miopic in her purpose, and whether it was an act of vengance, self-pity, or despair, she knew what she was doing. But the living, the pained persons she left behind, will never know her motives; but they will be haunted by her untimely death.