But they haven't had direct proof of the effect until now.

He had no direct proof, other than an unshakable belief.

After all, she had no direct proof of those whatsoever.

He said he had direct proof that former police officers led 58 of these.

Or it could be something entirely different, because we don't have direct proof.

I had my first direct proof of a changed world.

That is our fear, although we have no direct proof.

Yet there had been no direct proof of murder in those instances.

But direct proof against him that rises to American legal standards has been hard to obtain.

This legend, though is not borne out by any direct proof.