diff --git a/investigator-runtime/src/detectives/dupin.ts b/investigator-runtime/src/detectives/dupin.ts
index 6c28ea0..7f76f03 100644
--- a/investigator-runtime/src/detectives/dupin.ts
+++ b/investigator-runtime/src/detectives/dupin.ts
@@ -35,11 +35,13 @@ export interface DupinTask {
 }
 
 function renderChunkBlock(hits: SearchHit[], lang: "pt" | "en"): string {
-  const blocks = hits.map((h) => {
+  const blocks = hits.map((h, i) => {
     const text = (lang === "en" ? h.content_en : h.content_pt) || h.content_en || h.content_pt || "";
-    const pageStr = String(h.page).padStart(3, "0");
     return [
-      `--- ${h.doc_id}/p${pageStr}#${h.chunk_id} ---`,
+      `--- chunk ${i + 1} ---`,
+      `doc_id: ${h.doc_id}`,
+      `chunk_id: ${h.chunk_id}`,
+      `page: ${h.page}`,
       `type: ${h.type}`,
       h.classification ? `classification: ${h.classification}` : null,
       "",
@@ -108,13 +110,33 @@ export async function runDupin(task: DupinTask): Promise<
   const lang: "pt" | "en" = task.lang ?? "pt";
   const k = task.context_chunks ?? 18;
 
-  const hits = await hybridSearch({
+  // Pass 1: scoped to the requested doc, if any.
+  let hits = await hybridSearch({
     query: task.topic,
     lang,
     doc_id: task.doc_id ?? null,
     top_k: k,
     recall_k: 80,
   });
+  let scope_widened = false;
+
+  // Pass 2: if a doc_id was set and the head is too thin for a tournament,
+  // widen the scope to the whole corpus. Cross-doc contradictions are
+  // valuable too (one doc says X, another says Y).
+  if (task.doc_id && hits.length < 2) {
+    const widened = await hybridSearch({
+      query: task.topic,
+      lang,
+      doc_id: null,
+      top_k: k,
+      recall_k: 80,
+    });
+    if (widened.length > hits.length) {
+      hits = widened;
+      scope_widened = true;
+    }
+  }
+
   await audit({
     event: "dupin_grounded",
     job_id: task.job_id,
@@ -122,6 +144,7 @@ export async function runDupin(task: DupinTask): Promise<
     topic: task.topic,
     n_chunks: hits.length,
     doc_id: task.doc_id ?? null,
+    scope_widened,
   });
   if (hits.length < 2) {
     return { skipped: true, reason: "insufficient_corpus" };
diff --git a/investigator-runtime/src/tools/write_contradiction.ts b/investigator-runtime/src/tools/write_contradiction.ts
index 56ba7a6..d45391a 100644
--- a/investigator-runtime/src/tools/write_contradiction.ts
+++ b/investigator-runtime/src/tools/write_contradiction.ts
@@ -48,10 +48,20 @@ interface ResolvedPosition extends ContradictionPosition {
   page: number;
 }
 
+/**
+ * Strip page-prefix idioms detectives sometimes emit. Canonical chunk_id is
+ * just `c0042`. Forms accepted: "c0042", "p007#c0042", "p007/c0042".
+ */
+function normalizeChunkId(raw: string): string {
+  const m = raw.match(/c\d{4,}$/);
+  return m ? m[0] : raw;
+}
+
 async function resolveChunk(doc_id: string, chunk_id: string): Promise<{ chunk_pk: number; page: number } | null> {
+  const cid = normalizeChunkId(chunk_id);
   const row = await queryOne<{ chunk_pk: number; page: number }>(
     `SELECT chunk_pk, page FROM public.chunks WHERE doc_id = $1 AND chunk_id = $2`,
-    [doc_id, chunk_id],
+    [doc_id, cid],
   );
   return row ?? null;
 }