1. Deduction – logical reasoning or drawing conclusions from evidence.
   Example: Holmes’s powers of deduction were unmatched; he could tell a man’s profession from a footprint.

2. Meticulous – extremely careful and precise.
   He was meticulous in examining every detail of the crime scene.

3. Astute – very clever and perceptive.
   Watson admired Holmes’s astute understanding of human nature.

4. Premeditated – planned in advance, usually about a crime.
   The inspector concluded it was a premeditated murder.

5. Enigmatic – mysterious or puzzling.
   The stranger gave an enigmatic smile before disappearing.

6. Elusive – difficult to catch, define, or understand.
   The truth remained elusive despite Holmes’s efforts.

7. Inference – a conclusion drawn from evidence.
   From the muddy boots, Holmes made the inference that the suspect had been outdoors.

8. Scrutiny – close, critical examination.
   The alibi didn’t hold up under Holmes’s scrutiny.

9. Credibility – believability or reliability.
   The witness’s story lacked credibility.

10. Rational – based on logic or reason rather than emotion.
    Holmes always stayed rational, even under pressure.

11. Surmise – to guess without full proof.
    He surmised that the letter had been written in haste.

12. Discrepancy – an inconsistency or difference.
    Holmes noticed a discrepancy in the servant’s account.

13. Unfathomable – impossible to understand fully.
    Watson found Holmes’s thought process unfathomable.

14. Ominous – suggesting something bad will happen.
    An ominous silence filled the house before the scream.

15. Sinister – suggesting evil or harm.
    There was something sinister about the butler’s calm expression.

16. Vigilant – watchful and alert.
    Holmes stayed vigilant for any clue others might miss.

17. Perceptive – quick to notice and understand things.
    He was extremely perceptive about people’s motives.

18. Reconstruct – to piece together or rebuild an event.
    He reconstructed the crime scene step by step.

19. Intuitive – based on instinct rather than reasoning.
    Holmes’s intuitive leaps often startled Watson.

1. “Elementary, my dear Watson.” – The answer is simple and obvious.
   Elementary, my dear Watson — the footprints tell the whole story.

2. “The game is afoot.” – The adventure or investigation has begun.
   Holmes grabbed his coat: “The game is afoot!”

3. “Every clue tells a story.” – Every detail has meaning.
   Holmes examined the evidence carefully: “Every clue tells a story.”

4. “Nothing escapes my notice.” – Said by someone highly observant.
   “You changed your tie this morning,” Holmes said. “Nothing escapes my notice.”

5. “A case of mistaken identity.” – When someone is wrongly identified.
   It was a classic case of mistaken identity.

🧠 C1-Level Idioms Related to Mystery, Logic, and Investigation

1. Put two and two together – figure something out logically.
   Holmes put two and two together and realised who the killer was.

2. Read between the lines – understand hidden meanings.
   Watson struggled to read between the lines of Holmes’s clues.

3. Take something at face value – accept something as it appears without question.
   Holmes never took a confession at face value.

4. Out of the blue – unexpectedly.
   A new witness appeared out of the blue.

5. Turn a blind eye (to something) – deliberately ignore something wrong.
   The police turned a blind eye to the suspect’s connections.

6. The tip of the iceberg – a small part of a much larger issue.
   The missing jewel was just the tip of the iceberg.

7. Hidden in plain sight – obvious, but overlooked.
   The clue was hidden in plain sight the whole time.

8. Get to the bottom of something – find the true cause or reason.
   Holmes promised to get to the bottom of the mystery.

9. In the dark (about something) – unaware or uninformed.
   Watson was completely in the dark about Holmes’s plan.

10. A red herring – a misleading clue or distraction.
    The strange letter turned out to be a red herring.

11. Crack the case – solve the mystery.
    After days of investigation, Holmes finally cracked the case.

12. Jump to conclusions – make assumptions without enough evidence.
    Lestrade jumped to conclusions and arrested the wrong person.