The scene
Charity Market · Cash deskThe charity market's cash desk received a refund request for a purchase that never happened. The receipt looks correct but corresponds to no sale. Only three people used the printer during the shift.
The machine adds an automatic number to each slip. Although the amount could be entered freely, nobody could choose that number. The handover sheets record the series printed by each person.
What we know for certain
One of the three people printed the false receipt during their own shift. Numbers were assigned consecutively, with no resets, duplicates or remote printing. Nobody used the printer outside their time slot. The handover records are correct.
The three accounts
Amaya Costa
First cash-desk shift«I handed over the desk with my entire series accounted for.»
Biel Romero
Second cash-desk shift«My shift was quiet; I do not remember that refund.»
Cora Sanz
Third cash-desk shift«I printed only the receipts for the final sales.»
Examine the evidence
0 of 5 openedOpening these five clues does not cost points.
01The disputed receipt
The false receipt's automatic number is 218. It was neither added by hand nor pasted over another number.
02The first handover
Amaya printed every number from 201 to 210, including both endpoints.
03The second handover
Biel printed numbers 211 to 220. The handover sheet assigns every number in that range to his shift.
04Cora's closing shift
Cora began with 221 and ended with 230. She had not used the printer beforehand.
05The cash desk's memory
The memory confirms all three time slots. The amount and description were editable; the serial number was not.