On the night of October 12th, the ”Sunburst Medallion” was stolen from the highly secured display case in the city museum. The theft occurred sometime between the museum closing at 10:00 PM and the night guard, Mr. Hemant, completing his final round at 1:00 AM. Three primary suspects were identified, all of whom had recently been dismissed from their museum positions: Anjali, the former curator; Bharat, the former security expert; and Chitra, the former exhibits designer.
Here are the established facts and their alibis:
• The security system logs show that the display case was opened using a specific five-digit code, which only Anjali and the museum director (who was out of the country) knew.
• Bharat’s alibi is that he was at a distant relative’s birthday party from 8:00 PM to 1:30 AM. Multiple independent witnesses confirmed his presence throughout the entire period.
• Chitra’s alibi is that she was working late at a downtown graphic design studio. A timestamped security camera from the studio’s entrance shows her entering at 7:00 PM and exiting at 11:45 PM. The studio is a 20-minute drive from the museum.
• Mr. Hemant, the night guard, stated he checked the medallion at 10:30 PM, and it was still there.
• Further investigation revealed that a small, distinctive silver button was found near the display case. Anjali is known to frequently wear a coat with similar unique silver buttons. The security expert, Bharat, had previously boasted that he could remotely disable a
certain type of magnetic lock-the same type used on the medallion’s case-without needing the code, though the log suggests the code was used. (269 words)
Identifying the Logical Flaw in the Argument :
A detective argues: ”Since Bharat has a confirmed, continuous alibi covering the entire time window of the theft (10:30 PM to 1:00 AM), he cannot be the thief.” What principle of logic supports this detective’s conclusion?
Correct Answer :
If an event requires presence, confirmed absence proves innocence
Solution :
Correct Answer: If an event requires presence, confirmed absence proves innocence
Step-by-Step Explanation:
1. Understanding the Detective's Argument:
The detective claims that because Bharat was verified to be at another location (a birthday party) continuously from 8:00 PM to 1:30 AM, he could not have committed the physical theft at the museum which occurred between 10:30 PM and 1:00 AM.
2. Identifying the Underlying Logical Principle:
The act of stealing an item directly from a physical display case requires physical presence at the scene at the time of the crime. Logically, if a crime requires physical presence (Event P requires Presence X), and it is definitively proven that a person was absent from that place during that timeframe (Not Presence X), then that person could not have performed the physical act (Not Event P).
3. Evaluating the Options:
• Correlation does not imply causation: Refers to confusing sequential or simultaneous events with causal relationships, which is irrelevant to proof by alibi.
• If an event requires presence, confirmed absence proves innocence: This directly describes Modus Tollens applied to presence and action (If P, then Q; Not Q, therefore Not P). Confirmed absence invalidates the necessary condition for committing the physical theft.
• The rule of double jeopardy: A legal protection preventing someone from being tried twice for the same crime, unrelated to evaluating alibis.
• The burden of proof lies with the accuser: A legal standard regarding who must prove a claim, not a principle explaining why an alibi logically eliminates a suspect.
Thus, the detective's conclusion relies on the fundamental logical principle: "If an event requires presence, confirmed absence proves innocence".
Access expert-curated educational resources and study materials—completely free.
Create, conduct, and manage professional online assessments with Mindyard. Perfect for teachers and institutes.
Copyright © 2026 Mindyard. All Rights Reserved.
