The very first scene where Arthur Conan Doyle shows what this hero is capable of:
[After the investigation of the crime scene, which included "Rache" on the wall, assumed by Lestrade, a police detective, to be an unfinished "Rachel"]
"I'll tell you one thing which may help you in the case," [Holmes] continued turning to the two detectives. "There has been murder done, and the murderer was a man. He was more than six feet high, was in the prime of life, had small feet for his height, wore coarse, square-toed boots and smoked a Trichinopoly cigar. He came here with his victim in a four-wheeled cab, which was drawn by a horse with three old shoes and one new one on his off fore-leg. In all probability the murderer had a florid face, and the finger-nails of his right hand were remarkably long. These are only a few of the indications, but they may assist you."
Lestrade and Gregson glanced at each other with an incredulous smile.
"If this man was murdered, how was it done?" asked the former.
"Poison," said Sherlock Holmes curtly, and strode off. "One other thing, Lestrade," he added, turning round at the door: "'Rache' is the German for 'revenge'; so don't lose your time looking for Miss Rachel."
With which Parthian shot
he walked away, leaving the two rivals open-mouthed behind him.
The ending of A Case of Identity when Holmes confronts Windibank over the breaking of his marriage engagement to Holmes' client:
- A Study In Scarlet is just one big CMOA all the way through.
“The law cannot, as you say, touch you,” said Holmes, unlocking and throwing open the door, “yet there never was a man who deserved punishment more. If the young lady has a brother or a friend, he ought to lay a whip across your shoulders. By Jove!” he continued, flushing up at the sight of the bitter sneer upon the man’s face, “it is not part of my duties to my client, but here’s a hunting crop handy, and I think I shall just treat myself to—” He took two swift steps to the whip, but before he could grasp it there was a wild clatter of steps upon the stairs, the heavy hall door banged, and from the window we could see Mr. James Windibank running at the top of his speed down the road.
- It should also be added that this is a rare research error on Doyle's part, as breaking a promise to marry was actionable in civil court at the time, and Miss Sutherland (or, more likely, her stepfather) could have easily filed suit with Holmes' information and testimony in hand.
- One problem. Her stepfather is Windibank. Although women were allowed to bring Breach of Promise suits by themselves; she could also have gotten Holmes to do it for her, as "by her friend".
- A problem with that, too, since it was made quite clear she wasn't going to, being still completely in love with him.
- However, it could be that Holmes was so offended at the nature of the deception he wanted to avenge Miss Sutherland's honor personally.