Pardot Kynes was killed in a rock fall at Two Birds.
The Imperial planetologist on Arrakis, Kynes discovered that there had once been surface water on the planet. He came into contact with the Fremen after he saved some young boys that were being attacked by a Harkonnen patrol, and tried to persuade the Fremen to help him turn Arrakis into a lush planet with relatively small areas of desert. The Fremen, after much deliberation, ordered him killed, as tradition dictated. His killer, Uliet, approached him while he was lecturing. Kynes simply told Uliet to “Remove yourself” and walked past him. Uliet took three steps and deliberately fell on his crysknife. This was taken to be a sign from god, and so the Fremen allowed Kynes to live. Kynes married a Fremen woman and had a son, Liet Kynes.
Desert fremen are always made welcome in his residences, and he is always welcome in any sietch.