The Detective’s DeskPEN & PAPER · CASE FILE
Pen & Paper · A research garden at closing time
A professor dies after a private visit, but the first sample result appears clean. One person may have killed him and another may have helped afterward. Establish their different roles rather than assuming that every collaborator planned the death.
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.
Linden’s sealed private drink and two differently labelled laboratory samples are secured. The examination places the fatal exposure during 18:25–18:32. A complete door-camera record covers the glasshouse during that interval.
Laboratory technician
I took over the sample bench at 18:25. I changed a damaged label, but never entered the glasshouse before the alarm.
Ada knew I had failed a certification review. She threatened to disclose it.
The waste log records two labels for sample G4, although only one vial was tested.
Research secretary
I left the glasshouse at 18:20. The laboratory technician signed all samples afterward.
Professor Linden intended to report my sale of unpublished formulas.
Finn often changes labels when the printer jams; that is not unusual.
Foundation trustee
I was at the library seminar beside Leila. The wide recording shows both of us.
I had received a complaint about Ada selling formulas. I asked Linden to preserve the originals.
Linden’s 18:24 message says he was expecting Ada to explain the missing notebook.
Visiting botanist
I was on a live seminar camera in the library. I criticised Linden’s methods during questions.
He had used my photographs without permission. I planned a public complaint.
He kept his own drink inside the glasshouse, separate from the sample bench.
Greenhouse engineer
I inspected the outer irrigation pipes with a trainee. The body camera records both of us.
He was withholding my final maintenance payment.
The glasshouse side vent is too small for a person. The door contact was working.
Graduate researcher
I used the instrument room’s continuous microscope recorder until 18:40.
I feared losing my scholarship if Linden’s project closed.
Ada came back for a yellow notebook after she said she had left.
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 · Library
Linden’s message asks Ada to explain the notebook at 18:25. Its server receipt predates the emergency and cannot have been written to support a later accusation.
Physical record · Glasshouse
Ada re-enters at 18:26 with a yellow notebook and leaves at 18:31. No other person enters during the exposure interval. The camera shows her handling the private drink on the desk.
Physical record · Glasshouse
The only person-sized access is the recorded door. The vent remains sealed. The private drink was clear before Ada’s arrival, according to its sealed 18:24 quality-control portion.
Physical record · Library
Leila and Ciro stay visible at the seminar, Oren with the trainee, and Ruth at the instrument recorder. Finn is at the sample bench during Ada’s visit. Nobody else reaches the private drink in that interval.
Physical record · Sample bench
At 18:41 Ada writes, “He is dead. Make the first result look clean; otherwise my visit ends us both.” Finn replies, “I will relabel the submitted vial.” There is no earlier agreement about harming Linden in the recovered exchange.
Physical record · Instrument room
Ruth’s recorder shows Ada returning toward the glasshouse at 18:26. It corroborates the independent door camera rather than merely repeating Ruth’s memory.
Physical record · Sample bench
Finn prints a new clean-control label at 18:43, after the emergency call, and attaches it to the incident sample slot. The original label is recovered underneath. His account of an earlier printer jam is inconsistent with the timestamps.
Physical record · Sample bench
Finn’s failed certification is real. Ada held a copy. This explains his fear, but the only established agreement concerns a false result after the death.
Physical record · Glasshouse
A sealed retained portion of Linden’s private drink contains the harmful marker associated with his death. The first laboratory report describes a different vial. It cannot clear the private drink.
Physical record · Glasshouse
The notebook contains dated sale records for Linden’s unpublished formulas and Ada’s acknowledgments of the buyers’ payments. Linden annotated a meeting request for 18:25.
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.
Compare the records with each account. Work out what the evidence establishes, then separate that finding from anything it does not prove.