When in doubt, tell the truth.
Truth is more of a stranger than fiction.
A good lie will have travled half way around the world while the truth is putting on her boots. I was gratified to be able to answer promptly, and I did. I said I didn't know. A powerful agent is the right word. Whenever we come upon one of those intensely right words in a book or a newspaper the resulting effect is physical as well as spiritual, and electrically prompt.