Mystery · Logic · Immersive Play
Look closer. Think deeper. Find the truth.
Murder-mystery casebooks where you are the detective, and a fresh code to crack every day. Train your logical thinking and sharpen your mind through mystery puzzles.
The Casebooks
Choose your next case
A growing collection of casebooks, grouped by series. Every logic casebook is a complete mystery with carefully built clues and one answer you can check here.
Murder-Mystery Casebook Puzzles
Full-size casebooks: 11,016 suspect records, 20 essential clues, one killer.
Halloween Case Files
Halloween nights in the early 1930s. 11,016 suspects in every case.
The Armchair Detective Casebook
Cryptogram puzzle books for adults: crack the code, one letter at a time.
The Wrongly Accused Murder Mysteries
Interactive logic mysteries: follow the evidence and clear the wrongly accused.
A Complete Mystery Case
Each casebook is a self-contained investigation: a victim, a locked room, thousands of records and the clues to narrow them down to one.
Carefully Built Logic
No guesswork. Every elimination follows from the evidence, so a patient reader can always reach the truth.
Check Your Accusation
Think you have found the killer? Enter the suspect’s name and number to confirm your conclusion without spoiling anything else.
The Case File Letter
New cases, before anyone else
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The Mind Behind the Casebooks
Ivy X. Locke
Ivy X. Locke creates immersive mystery puzzle books that make logical thinking feel exciting. Each casebook asks you to read closely, question every record and follow the evidence wherever it leads.
About the author“The truth is rarely hidden from sight. More often, it is hidden by the way we choose to look.”
— Ivy X. Locke