I learned of a recent trend of nuclear scientists gone missing or found dead from Cryptogon.com. Unfortunately I found it easy to add to the list. Some of them have links to the Iran nuclear situation.
1. Ardeshir Hosseinpour
2. Lokanathan Mahalingam -Follow up here, body found.
3. Shahram Amiri
4. Timothy Hampton -Other articles here and here.
5. Antonio Ferrigno
6. Masoud Ali Mohammadi
7. Lachlan Cranswick
According to this article in the Telegraph, it is public knowledge that Isreal "has launched a covert war against Iran" including "the planned assassination of top figures involved in Iran's atomic operations."
That might explain some of the disappearances but I'm not sure about cases 2,4, 5, and 7 where I have not yet found the link to the Iran nuclear program. That doesn't mean it doesn't exist however. There might also be more then one cause to this phenomenon.