Exercise 005
Same month, different case
A machine report calls a string of municipal arrests one investigation. Test each link, read the machine's own numbers, and decide what the evidence supports.
Briefing
This is a fictional scenario. Every person, place, police unit, outlet and report below is invented, including the report tool.
You work at a small, fictional news desk. An automated tool called TIDEMARK collects news signals, scores them and writes short analyses. One analysis says that a run of municipal corruption arrests in Northmark Province is a single investigation. A colleague wants to quote it. Your editor asks one question: which of its links hold up?
Today is Monday 20 April 2026. The pack below has the report, four sources and the tool’s search log. All the evidence you need is on this page.
The TIDEMARK report
Northmark’s tender investigation: one probe, four chapters
Published 18 April.
- On 16 April, police arrested four senior officials of Stonebridge Municipality on fraud and corruption charges.
- The arrests are a later phase of the Alder Cross tender probe that began in September 2025.
- Police raided the Alder Cross City Council offices in September 2025.
- The four were arrested in Alder Cross, which confirms the link to the council probe.
- Both cases involve the same police unit.
- A search warrant at the council in September 2024 shows the same pattern.
- More arrests are expected.
Case record: 6 pinned signals. Evidence confidence: 0.30. Gravity score of each pinned signal: 0.30.
Source A: Northmark Gazette, Thursday 16 April 2026
The Northmark Serious Corruption Team arrested four senior officials of Stonebridge Municipality in Alder Cross on Wednesday. The four work at the municipality’s head office in Stonebridge, about 90 km from the provincial capital. They are charged with fraud and corruption and accused of bypassing tender procedures. A Team spokesperson said the case comes from incidents reported in September 2024 and has been under investigation since. The four are due in the Kelder Magistrate’s Court on Friday. The spokesperson said more arrests are expected.
Source B: Capital Courier, Wednesday 17 September 2025
Officers of the Northmark Serious Corruption Team visited the offices of the Alder Cross City Council on Wednesday morning. A Team spokesperson said they were executing a court order to obtain documents for an investigation into alleged tender corruption involving the city manager’s office. Two opposition parties welcomed what they called “a raid”. The Team did not say whether anyone would be charged.
Source C: Alder Cross City Council media statement, Thursday 18 September 2025
No raid took place. The Team presented a court order for specific tender documents and the council supplied them the same morning. The council is cooperating fully. The statement does not comment on the allegations.
Source D: Capital Courier, Friday 6 September 2024
Police executed a search warrant at the Alder Cross City Council offices on Thursday as part of the investigation into the collapse of Orchard Bank. A police spokesperson said the warrant was for records of the council’s deposits with the bank. The collapse is being investigated by a separate commercial crimes unit.
The tool’s search log
Query 1:
alder cross council tender corruption police raid: 0 resultsQuery 2:
alder cross council police: 14 resultsPinned signals: Source A, two other reports of the Stonebridge arrests, Source B, Source C and Source D. Each scored 0.30.
Tasks
- Timeline. Make a table of every event in the pack: date, place, which body acted, and what the source says the matter is about. Include the September events and the April arrests.
- Claim table. For each of the seven numbered claims, mark it Supported, Partly supported, Contradicted or Unsupported (no source in the pack), and name the source you used.
- The word “raid”. Sources B and C describe the same morning differently. What do they agree happened? Whose word is “raid”? Should claim 3 use it?
- Where someone is arrested. Claim 4 treats the place of arrest as evidence. What does Source A say about where the four work, and what does a place of arrest tell you about a case?
- The numbers and the search. (a) Every pinned signal scores 0.30 and the case’s evidence confidence is 0.30. What does that tell you about the score? (b) Query 1 returned nothing and Query 2 returned 14 results. Check which of Query 1’s words appear in each of Sources B, C and D, and say what an empty search does and does not show.
- Verdict. In 150 words or fewer, say what the pack supports, what the report joined without support, and what you cannot tell.
Hints
Hint 1 (task 1)
Sort the rows by date and mark the ones that share a month. Add a column for what each matter is about, in the source’s own words, not the report’s.
Hint 2 (task 2)
Ask what each kind of link would need: a source that says the matters are connected, the same alleged conduct, or the same case in court. Similar timing, the same unit and the same place are not on that list.
Hint 3 (task 3)
Separate what happened (officers, a court order, documents) from what it was called. Then check who is speaking in each source.
Hint 4 (task 4)
Look at the distance in Source A. Then ask what a place of arrest could mean other than “this is where the crime happened”.
Hint 5 (task 5a)
If you scored six different reports and every score came out identical, what would you conclude about the scorer?
Hint 6 (task 5b)
Write out Query 1’s seven words. Tick each one off against the text of Source B, then C, then D. Does any single source contain all seven?
Solution
Solution (spoiler)
1. Timeline.
| Date | Place | Who acted | Matter, per the source |
|---|---|---|---|
| September 2024 (reported) | Stonebridge Municipality | Incidents reported, later investigated by the Team | Bypassing tender procedures (A) |
| Thursday 5 September 2024 | Alder Cross City Council | Police, search warrant | Collapse of Orchard Bank, council deposits (D) |
| Wednesday 17 September 2025 | Alder Cross City Council | Northmark Serious Corruption Team, court order for documents | Alleged tender corruption in the city manager’s office (B, C) |
| Wednesday 15 April 2026 | Four Stonebridge officials, arrested in Alder Cross | Northmark Serious Corruption Team | Fraud, corruption, bypassing tender procedures (A) |
Three events fall in September, across two years. Two of them are in September 2024 and are different matters.
2. Claim table.
| # | Claim | Finding | Why |
|---|---|---|---|
| 1 | Four officials arrested on 16 April | Partly supported | Source A: arrested on Wednesday, which was 15 April. 16 April is the date of the report. |
| 2 | A later phase of the Alder Cross tender probe | Unsupported | Source A describes a Stonebridge case that traces to incidents reported in September 2024. Source B describes a separate matter at the council. No source says they are one investigation. |
| 3 | Police raided the council in September 2025 | Partly supported | Sources B and C agree officers came with a court order and obtained documents. “Raid” is a label used by two opposition parties in B and denied in C. |
| 4 | Arrested in Alder Cross, which confirms the link | Partly supported | The place of arrest is supported (A). The inference is not: the four work 90 km away in Stonebridge, and a place of arrest says where officers found them, not which investigation they belong to. |
| 5 | Both cases involve the same police unit | Supported | A and B name the same Team. It does not support the link: a unit runs many investigations at once. |
| 6 | A 2024 search warrant at the council shows the same pattern | Unsupported | Source D is about the collapse of a bank, investigated by a separate unit. No source calls it the same pattern, and D points the other way. |
| 7 | More arrests are expected | Partly supported | Source A says so, for the Stonebridge case only. Nothing says it about the council matter. |
3. The word “raid”. Both sources agree that officers of the Team came to the council on the morning of 17 September 2025 with a court order and the council handed over specific documents. “Raid” is the word of two opposition parties, quoted in Source B. The council rejects it in Source C, and the Team spokesperson in B describes executing a court order for documents. Claim 3 should say what happened and note that the label is disputed. Printing “raided” as fact adopts one side’s word.
4. Where someone is arrested. Source A says the four work at the municipality’s head office in Stonebridge, about 90 km from the provincial capital, and were arrested in Alder Cross. A place of arrest tells you where officers found the suspects. It does not tell you which case they belong to, and the sources do not say why the arrest happened there. The report matched a place name instead of a case.
5. The numbers and the search.
(a) A scorer that gives six different reports the same number is not measuring how they differ. The evidence confidence of 0.30 is then the average of one repeated value. It cannot tell a strong case from a weak one, and the pack suggests it is a default rather than a measurement.
(b) Query 1 has seven words: alder, cross, council, tender, corruption, police, raid. Source B has six of them but not “police”. Source C has “council”, “tender” and “raid” (and “Alder Cross” in its heading) but not “corruption” or “police”. Source D has “police” and the council but not “tender”, “corruption” or “raid”. No single source has all seven, so a search that needs every word finds nothing. News also describes one event in different words: “visited”, “court order”, “documents”, “search warrant”. An empty search shows that those words did not match. It does not show that the event did not happen.
6. Sample verdict. The pack supports a real arrest of four Stonebridge officials by the Northmark Serious Corruption Team on Wednesday 15 April (reported 16 April), in a case traced to incidents reported in September 2024. It supports a court-ordered document request at Alder Cross City Council on 17 September 2025, which the council says was not a raid, and a separate bank-collapse search warrant at the council in September 2024. It does not support the report’s links: same month, same unit and a shared place of arrest are not evidence of one investigation, and no source says the matters are connected. The 0.30 scores are identical and measure nothing. I cannot tell whether a link exists, only that this pack does not show one. All matters are allegations.
Scoring (10 points, pass at 7).
- Timeline, 1 point: for four correct events with dates and matters.
- Claim table, 3 points: 3 for seven correct rows with sources, 2 for five or six, 1 for three or four, 0 for fewer.
- The word “raid”, 1 point: for separating what happened from what it was called.
- Where someone is arrested, 1 point: for saying a place of arrest does not show which case a person belongs to.
- Numbers and search, 2 points: 1 for saying identical scores measure nothing, 1 for explaining the empty search and saying an empty search is not an empty world.
- Verdict, 2 points: 1 for what the pack supports and what the report got wrong, 1 for stating limits (allegations, no link shown is not no link).
Debrief
Six habits this exercise is built to teach:
- The same month is not the same case. Three events fell in September and were three different matters.
- The same unit is not the same investigation. A police unit runs many cases at the same time.
- Where someone was arrested is not what they are accused of. A place of arrest is a fact about the arrest.
- A label is a claim. “Raid” is a word someone chose. Say who chose it.
- An empty search is not an empty world. Try the event in different words before you write “no source found”.
- A score that never changes measures nothing. If every item scores the same, the number is a default.
For the checks this builds on, try Exercise 004: One arrest, wrong map. For the real audit and rebuild behind this exercise, read A polished report is not a checked report and its follow-up, Checking the check.
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