Guards! Guards!

guilty in general terms.
    “Mmmmmuh,” said Brother Fingers.
    Sergeant Colon gently lifted the lid of the top box.
    “What do you make of it, Sergeant?” said Vimes, stepping back.
    “Er. It looks like a Klatchian Hots with anchovies, sir,” said Sergeant Colon knowledgeably.
    “I mean the man,” said Vimes wearily.
    “Nnnnn,” said Brother Fingers.
    Colon peered under the hood. “Oh, I know him, sir,” he said. “Bengy ‘Lightfoot’ Boggis, sir. He’s a capo de monty in the Thieves’ Guild. I know him of old, sir. Sly little bugger. Used to work at the University.”
    “What, as a wizard?” said Vimes.
    “Odd job man, sir. Gardening and carpentry and that.”
    “Oh. Did he?”
    “Can’t we do something for the poor man?” said Lady Ramkin.
    Nobby saluted smartly. “I could kick him in the bollocks for you if you like, m’lady.”
    “Dddrrr,” said Brother Fingers, beginning to shake uncontrollably, while Lady Ramkin smiled the iron-hard blank smile of a high-born lady who is determined not to show that she has understood what has just been said to her.
    “Put him in the coach, you two,” said Vimes. “If it’s all right with you, Lady Ramkin—”
    “—Sybil—” corrected Lady Ramkin. Vimes blushed, and plunged on—“it might be a good idea to get him indoors. Charge him with the theft of one book, to whit, The Summoning of Dragons .”
    “Right you are, sir,” said Sergeant Colon. “The pizzas’re getting cold, too. You know how the cheese goes all manky when it gets cold.”
    “And no kicking him, either,” Vimes warned. “Not even where it doesn’t show. Carrot, you come with me.”
    “DDddrrraa,” Brother Fingers volunteered.
    “And take Errol,” added Vimes. “He’s driving himself mad here. Game little devil, I’ll give him that.”
    “Marvellous, when you come to think about it,” said Colon.
    Errol was trotting up and down in front of the ravaged building, whining.
    “Look at him,” said Vimes. “Can’t wait to get to grips.” His gaze found itself drawn, as though by wires, up to the rolling clouds of fog.
    It’s in there somewhere, he thought.
    “What we going to do now, sir?” said Carrot, as the carriage rattled off.
    “Not nervous, are you?” said Vimes.
    “No, sir.”
    The way he said it jogged something in Vimes’s mind.
    “No,” he said, “you’re not, are you? I suppose it’s being brought up by the dwarfs that did it. You’ve got no imagination.”
    “I’m sure I try to do my best, sir,” said Carrot firmly.
    “Still sending all your pay home to your mother?”
    “Yes, sir.”
    “You’re a good boy.”
    “Yessir. So what are we going to do, Captain Vimes?” Carrot repeated.
    Vimes looked around him. He walked a few aimless, exasperated steps. He spread his arms wide and then flopped them down by his sides.
    “How should I know?” he said. “Warn people, I guess. We’d better get over to the Patrician’s palace. And then—”
    There were footsteps in the fog. Vimes stiffened, put his finger to his lips and pulled Carrot into the shelter of a doorway.
    A figure loomed out of the billows.
    Another one of ’em, thought Vimes. Well, there’s no law about wearing long black robes and deep cowls. There could be dozens of perfectly innocent reasons why this person is wearing long black robes and a deep cowl and standing in front of a melted-down house at dawn.
    Perhaps I should ask him to name just one.
    He stepped out.
    “Excuse me, sir—” he began.
    The cowl swung around. There was a hiss of indrawn breath.
    “I just wonder if you would mind— after him, lance-constable !”
    The figure had a good start. It scuttled along the street and had reached the corner before Vimes was halfway there. He skidded around it in time to see a shape vanish down an alley.
    Vimes realized he was running alone. He panted to a halt and looked back just in time to see Carrot jog gently around the corner.
    “What’s wrong?” he wheezed.
    “Sergeant Colon said I wasn’t to run,” said Carrot.
    Vimes looked at him vaguely. Then slow comprehension dawned.
    “Oh,” he said. “I, er, see. I don’t think he meant in every circumstance, lad.” He stared back into the fog. “Not that we had much of a chance in this fog and these streets.”
    “Might have been just an innocent bystander, sir,” said Carrot.
    “What, in Ankh-Morpork?”
    “Yes, sir.”
    “We should have grabbed him, then, just for the rarity value,” said