It's my business to watch things.

So I noticed you talking to the police officer; I also noticed the patrol wagon standing on the opposite side of the street for nearly an hour--my report on that will amuse them at headquarters, won't it?
And I noticed you nod to the bruiser, just as your victim came out." "Let go of my arm, sir!" "Do you prefer handcuffs?
I arrest you.

We'll run over to the station and explain things." "Do you know who I am ?" "Perfectly, Mr.Mershone.I believe I ran you in for less than this, some two years ago.

You gave the name of Ryder, then.

Better take another, to-night." "If you're the house detective, why do you mix up in this affair ?" enquired Mershone, his anxiety showing in his tone.
"Your victim was a guest of the house." "Not at all.