There are various ways to call a man a liar. One way is just to scream it at him, which doesn't prove anything. Another is to establish facts by long and patient investigation. Still another way is not to call him a liar at all – let him do it himself.
Bosh. I find a rival – but no, I won't flatter myself that Tecumseh Fox would consider himself a rival of Dol Bonner – I find an eminent detective in your apartment, and that alone is enough, without adding that he is concealed in your bedroom while I am discussing my business with you...
There are only two kinds of books which you can write and be pretty sure you're going to make a living – cook books and detective stories.