how do you say "first-hand knowledge" in Sspanish?

Question

as used in this context, "Do you have first-hand knowledge of what Bill told the professor?"

Answer 1

Es de primera mano...

The same as in English, to mean exactly the same.

Although we don't say knowledge but use "source"

Esto es de una fuente de primera mano...

Answer 2

An easy way to go about answering that, although indirect (sorry), is to say "original" in the place of "first-hand." The easy part about this is that "original" is also "original" in Spanish.