The Detective’s DeskLeo Venn
Duty officer
What happened from your point of view?
I secured the old reading room after a flood before the claimed visit.
What should I check independently?
The safety closure and key custody were logged by a separate municipal team.
HARD · CASE FILE
The Alibi Written by One Person
Hard · A collection store and a closed reading room
Three records appear to confirm an alibi, but they may all repeat one person’s claim. Trace which sources are independent, who removed the original and whether anyone agreed to write a false visit beforehand.
Read the case file below, or open the interactive desk to examine records, keep notes and submit your reasoning. These are the case materials, without the solution.
The scene
The codebook is recovered on site. The old reading room had a documented safety closure. All relevant source records are preserved, including the origin of the daily visitor report.
People and accounts
Ciro Lake
Membership secretary
What happened from your point of view?
Mira and I spent the evening together in the old reading room. Ruth’s report confirms it.
What should I check independently?
I completed the signed visitor card before the evening began.
Ruth Hart
Visitor-book assistant
What happened from your point of view?
I can confirm that Mira and Ciro were at the reading room. I copied their visit into the daily report.
What should I check independently?
I did not personally see either person there; my source was Ciro’s signed card.
Mira Shaw
Collection borrower
What happened from your point of view?
I was with Ciro in the reading room. I could not have visited the store.
What should I check independently?
I had asked to buy the codebook privately and was refused.
Tomas Reed
Collection donor
What happened from your point of view?
I remained at the public desk. I had overstated my contribution to the catalogue, and I initially concealed that.
What should I check independently?
The actual missing object is a green-stitched codebook, not my donated catalogue.
Case records
Read each record on its own terms. A claim made by a person is different from a fact established by an independent record.
Physical record · Visitor desk
Donor’s catalogue correction
Tomas’s overstated catalogue contribution is real but concerns another publication. The public-desk record keeps him away from the codebook removal.
Physical record · Closed reading room
Independent safety closure
The municipal team closes the reading room before the claimed visit, retains its only access key and keeps the closure seal intact until the next morning. The pair could not have attended it as claimed.
Physical record · Visitor desk
The prewritten agreement
Before the removal Ciro writes, “Take the stitched book; I will sign that we were both at the closed room.” Mira replies that she will collect it using that cover.
Physical record · Collection store
Supervised sleeve recovery
The codebook is found in Mira’s detained sleeve with its accession mark and green stitch intact. Its identity matches the store record.
Physical record · Collection store
Store handling record
The checked store camera clearly identifies Mira removing the green-stitched codebook into her document sleeve during the claimed reading-room visit.
Physical record · Visitor desk
Ruth’s original copying task
Ciro asks Ruth to transcribe a signed membership card as supplied. She was not told the room was closed or that a codebook would be removed. Her source note openly identifies the card.
Physical record · Visitor desk
Signed visitor card
Ciro signs that he and Mira attended the old reading room. He completes the card before the claimed evening visit. A later system summary imports this same card.
Physical record · Visitor desk
Daily report source note
Ruth’s report and the automated attendance summary both cite Ciro’s card. Neither adds a personal sighting or a separately checked entry.
Questions to resolve
Who removed the original codebook?
Who knowingly supplied a false alibi before the removal?
How many independent personal sightings do the card, report and imported summary establish?
Whose record openly repeats a supplied source without established knowledge of the plan?
Use the interactive case desk to select your finding and cite the records that support it. The answer is checked there, and your progress stays in your browser.
Build your finding
Compare the records with each account. Work out what the evidence establishes, then separate that finding from anything it does not prove.