O. Henry never states what sorts of illegal activities Silky Bob has been up to out West or why the Chicago police want to talk to him. This is evidently because the author wants to mitigate the effect upon the reader when Jimmy betrays his old comrade. If Bob had been wanted for a really serious crime, such as bank robbery or even murder, the reader might feel that Jimmy’s behavior was treacherous and reprehensible, because he could be sending his old friend off to life imprisonment or execution. The reader has no cause to dislike Silky Bob. He seems like a generous, likeable, and loyal man.
O. Henry uses several subtle literary touches to make it seem that Bob’s arrest may be a blow to him but not a catastrophe. For one thing, the plain clothes man treats him with courtesy when he arrests him, while at the same time Bob makes no effort to resist or escape.
“You’ve been under arrest for ten minutes, ‘Silky’ Bob. Chicago thinks you may have dropped over our way and wires us she wants to have a chat with you. Going quietly, are you? That’s sensible.”
The arresting officer even hands Bob a note in which Jimmy apologizes for what he has done. If Bob were a dangerous fugitive, the detective would have slapped handcuffs on him, roughed him up, and possibly even pulled his gun. The police in O. Henry’s day were brutal.
The nickname “Silky" Bob suggests two things. One is that Bob is slick and smooth. No doubt he is a confidence man and never uses violence. The other thing the nickname suggests is that he likes luxury. He is the sort of man who would wear silk shirts, silk underwear, silk neckties, and sport a silk handkerchief in his breast pocket. Looking prosperous instills confidence in others, and he knows it. This sort of man is not a hood. He has made his money by selling worthless stock to yokels and other such con games. O. Henry describes such con men in a story titled “The Man Higher Up.” He knew such men personally, both in prison and outside.
Bob is probably slick and smooth enough to talk his way out of whatever kind of grilling the Chicago police have in store for him. According to the detective who arrests him, they only want to have a “chat.” They probably only have reports of crimes committed by a man with Bob's appearance and modus operandi. It doesn’t sound too serious, and therefore the reader doesn’t feel too much antipathy towards Jimmy Wells for double-crossing his friend.
On of the most significant passages in the story is found in Bob’s conversation with the cop whom he does not recognize as his old pal Jimmy.
“I’ve had to compete with some of the sharpest wits going to get my pile. A man gets in a groove in New York. It takes the West to put a razor-edge on him.”
This seems to prove that "Silky" Bob has been living by his wits and not by anything as gross as burglary or robbery. He is obviously a smooth character and a fast talker. He is completely at ease when confronted in the doorway by the uniformed cop, even though he must be aware that there are a number of cities and towns in which the police would like to have a “chat” with him.
The story ends without the reader knowing what is going to happen when Bob gets to Chicago, but he has undoubtedly been in a lot of scrapes during the past twenty years, and may have even served time in prison, like O. Henry himself. It seems likely that he will stonewall the Chicago police and walk away a sadder and a wiser man.