DxDetective case

A Birthday Card Comes Back After a Move

Murtek · Fictional learning case

Source organizations: U.S. government.

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Case overview

Ruth Collins sends her brother Sam a birthday card just after he moves. A few days later, the card is back on her front step with a short mark on the envelope. Sam insists he copied the details from their last text exchange. Ruth knows he did, because she watched him do it. Still, the card has made the trip back without reaching him. They spread the move notes across Ruth’s kitchen table and start with the plain facts: when Sam moved, when the card was sent, and which part of the note came from where. One missing detail could explain the whole detour. Or the timing could be playing tricks on them. The case begins with two siblings, a birthday card, and a mystery small enough to overlook until it starts repeating.

Characters

  • Ruth Collins sister
  • Sam Collins brother who moved
Difficulty
Intro
Estimated time
7 min
Rounds
1
Action options
6
Diagnostic options
3
Access
Free

Categories

household observation move context pattern reasoning

Skill focus

timing-context gathering evidence comparison privacy-aware communication proportionate next action

Diagnostic option types

timing and marking notes move-note comparisons shared-building context questions