It is possible that:
* This is a fictional character: There may be a character named Claire Sombert in a book, movie, or other work of fiction.
* The name is misspelled: Double-check the spelling to see if you are looking for a different person.
* The information is not publicly available: This person may have lived a private life and their death was not reported publicly.
If you can provide more context about where you encountered this name, I may be able to give you a more helpful answer.