It is a case of taking the man.

I have made my case out, and it seems I was wrong.

Young Charpentier could not have been engaged in this second affair.

Lestrade went after his man, Stangerson, and it appears that he was wrong too.
You have thrown out hints here, and hints there, and seem to know more than we do, but the time has come when we feel that we have a right to ask you straight how much you do know of the business.

Can you name the man who did it ?" "I cannot help feeling that Gregson is right, sir," remarked Lestrade.
"We have both tried, and we have both failed.