He was dressed in a bottle-green coat with a black velvet collar; wore white trousers; and carried a smart bamboo cane under his arm.

He had taken up a book from the stall, and there he stood, reading away, as hard as if he were in his elbow-chair, in his own study.

It is very possible that he fancied himself there, indeed; for it was plain, from his abstraction, that he saw not the book-stall, nor the street, nor the boys, nor, in short, anything but the book itself: which he was reading straight through: turning over the leaf when he got to the bottom of a page, beginning at the top line of the next one, and going regularly on, with the greatest interest and eagerness.
What was Oliver's horror and alarm as he stood a few paces off, looking on with his eyelids as wide open as they would possibly go, to see the Dodger plunge his hand into the old gentleman's pocket, and draw from thence a handkerchief! To see him hand the same to Charley Bates; and finally to behold them, both running away round the corner at full speed! In an instant the whole mystery of the hankerchiefs, and the watches, and the jewels, and the Jew, rushed upon the boy's mind.
He stood, for a moment, with the blood so tingling through all his veins from terror, that he felt as if he were in a burning fire; then, confused and frightened, he took to his heels; and, not knowing what he did, made off as fast as he could lay his feet to the ground.
This was all done in a minute's space.

In the very instant when Oliver began to run, the old gentleman, putting his hand to his pocket, and missing his handkerchief, turned sharp round.

Seeing the boy scudding away at such a rapid pace, he very naturally concluded him to be the depredator; and shouting 'Stop thief!' with all his might, made off after him, book in hand.
But the old gentleman was not the only person who raised the hue-and-cry.