Answer
The correct answer is:
In both stories, the criminal is not punished through the legal system, but rather through other means.
In "The Adventure of the Blue Carbuncle," the thief, John Horner, is not prosecuted because it is discovered that he was framed by James Ryder. Instead, Holmes uses his leverage to ensure that Horner's employer, the Countess of Morcar, doesn't press charges and gives Horner a second chance.
In "The Adventure of the Three Students," the culprit, Gilchrist, confesses to Holmes before any official investigation is launched. Holmes convinces him to write a letter of apology to the victim, who agrees not to press charges.
Therefore, in both cases, justice is achieved through unconventional means and not through the legal system.
Step-by-step explanation: