diff --git a/chapter3/DESIGN.md b/chapter3/DESIGN.md
deleted file mode 100644
index b351cc8..0000000
--- a/chapter3/DESIGN.md
+++ /dev/null
@@ -1,105 +0,0 @@
-# Розділ 3 — «Невпізнаний» (working title)
-
-Co-op LAN detective, 2 players, Node + vanilla JS.
-Every playthrough is a **new random case** from a seed-based generator. Inspired by Shadows of Doubt.
-
-## Premise
-
-A body with no ID is found in the district. You get only **starting facts** (randomized per case):
-2–4 of e.g. a phone number on a scrap of paper, a footprint size, a fabric fiber, a tattoo,
-a keyring, a partial fingerprint. From there:
-
-- **Act I — Who died?** Identify the victim (DB queries, biometrics, missing persons, phone trace).
-- **Act II — Who did it, how, and why?** The killer is NOT on any suspect gallery. You build a
-  profile from traces and cross-reference the citizen database until one person fits.
-
-## Roles (asymmetric, both required)
-
-### Польовий детектив — top-down 2D district
-- Canvas top-down map of a **fixed hand-crafted compact district**: ~10 buildings
-  (apartment blocks, bar, diner, offices, shop, clinic, police HQ), walkable with WASD/arrows.
-- Enters buildings, searches rooms via hotspots, collects **samples**: DNA swabs, lifted prints,
-  photos, documents, objects. Samples go to the shared board; analyst processes them.
-- **Apartment access is legal-only**: public places open; private doors need a **key**
-  (found on the body, in a work safe, at a relative's — never just lying around) or a **warrant**
-  (requires pinned evidence pointing at that person/place).
-- **Interrogation of any NPC** — but evidence-gated: topics unlock only when you hold the
-  relevant pinned evidence (ch2 `requires:` pattern, generated).
-
-### Аналітик (поліцейський хакер) — the terminal
-- **Citizen DB**: ~50 generated residents. Query by **typed name (keyboard — wrong spelling =
-  wrong/no dossier)** or filter by attributes (blood type, shoe size, employer, address, print type).
-- **City map with addresses** — who lives/works where; mirrors the district and shows the
-  partner's live position.
-- **Labs & systems** (each a hands-on minigame, not a button):
-  - **DNA lab**: gel electrophoresis — pipette sample into lanes, visually match band patterns
-    against DB candidates. Wrong match = confidently wrong lead.
-  - **Fingerprints**: overlay lifted print on candidate prints, rotate/align, mark ridge points.
-    DB narrows only by print *type*; the final match is your eyes.
-  - **CCTV archive**: scrub recorded footage of the crime night (timestamps, not a live clock),
-    spot a figure matching the profile (height, coat, gait).
-  - **Phone records + triangulation**: call logs for a number, triangulate a phone across
-    cell towers onto the city map.
-- **Crypto/logic tasks** (analyst has a tech background — difficulty is allowed):
-  base64, Caesar/Vigenère and other classical ciphers, binary/hex conversion, **md5 password
-  cracking** for a suspect's email/laptop (weak password derivable from dossier facts: pet name +
-  birth year — detective work feeds the wordlist), and **one optional multi-stage Cicada3301-style
-  puzzle** guarding a bonus master-evidence cache. Puzzles are generated with the case.
-
-## No clock
-
-No time mechanic. Citizens have static current locations (at work or at home); all CCTV and
-phone data is archival (the crime night). Actions cost nothing but thought.
-
-## Case generator — standalone library
-
-`chapter3/casegen/` — pure JS, no DOM/no server deps, reusable anywhere
-(`generateCase(seed, opts)`):
-
-- **Deterministic from seed**: same seed → same case. Needed for saves and both-players sync;
-  also lets you share a good case with friends.
-- Generates: citizens (names, homes, jobs, relationships, biometrics, phones, current positions),
-  victim, killer, **motive** from template pool — jealousy/love triangle, debt/desperation,
-  blackmail turned fatal, silenced witness / mistaken identity, kidnapping-gone-wrong, and more
-  drawn from classic Holmes-style structures — method, and the full **evidence chain planted
-  backwards** from the solution to the starting facts.
-- **Red herrings by design**: every case plants 1–2 plausible false leads (a citizen with motive
-  and no alibi, a second print at the scene). **Fair-play rule: every false lead is disprovable**
-  by reachable evidence — the game may mislead, never cheat.
-- `opts` reserved for growth: `citizens`, `districts`, `difficulty` (only `seed` used at first).
-- **Fairness validator in test.js**: for many random seeds, prove the chain from starting facts to
-  (victim identity, killer, motive, means) is reachable, and every red herring is refutable.
-
-## Shared board & sync
-
-- Server: Node `http` for static files + **`ws`** for real-time sync (state actions AND live
-  field-player position). Session stores the **seed** + full state, **persisted to a JSON file
-  per session code** — quit anytime, resume with the same code (the game is sized for 2–3 evenings).
-- Evidence list and citizen/suspect list are both **interactive for both players**: tick,
-  cross out, highlight, hide, keyboard notes — all synced.
-
-## Finale — one shot
-
-Form with three pickers fed by the interactive lists: **ХТО** (from citizens),
-**ЯК / ЧИМ** (method/weapon), **ЧОМУ** (motive), each link requiring attached evidence.
-
-**Single accusation.** Submitting asks for explicit confirmation from *both* players.
-Wrong → **you're fired**: the real case unfolds on screen, game over. Right → full recap, rank
-based on evidence completeness and how few false leads you chased.
-
-## Dependencies policy
-
-Deps allowed, but only popular well-maintained packages, pinned versions, and only where stdlib
-genuinely falls short. Current plan: **`ws` only.** Explicitly not used: game engines (canvas 2D
-suffices), `express` (http.createServer suffices), `seedrandom` (mulberry32 is 5 lines),
-md5 libs (`node:crypto`).
-
-## Milestones
-
-1. `casegen` lib + fairness tests (the heart — everything else renders its output)
-2. Server: `ws` sync, sessions + seed + disk saves
-3. Analyst terminal: DB, typed queries, city map
-4. Field: top-down 2D district, movement, search, samples, keys/warrants
-5. Minigames: DNA gel, fingerprints, CCTV, triangulation
-6. Crypto tasks + Cicada puzzle
-7. Interrogations, finale form, firing ending, polish, README
diff --git a/detective-game/.gitignore b/detective-game/.gitignore
new file mode 100644
index 0000000..19ed07e
--- /dev/null
+++ b/detective-game/.gitignore
@@ -0,0 +1,147 @@
+# Logs
+logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+lerna-debug.log*
+
+# Diagnostic reports (https://nodejs.org/api/report.html)
+report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
+
+# Runtime data
+pids
+*.pid
+*.seed
+*.pid.lock
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+*.lcov
+
+# nyc test coverage
+.nyc_output
+
+# Grunt intermediate storage (https://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# Bower dependency directory (https://bower.io/)
+bower_components
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (https://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directories
+node_modules/
+jspm_packages/
+
+# Snowpack dependency directory (https://snowpack.dev/)
+web_modules/
+
+# TypeScript cache
+*.tsbuildinfo
+
+# Optional npm cache directory
+.npm
+
+# Optional eslint cache
+.eslintcache
+
+# Optional stylelint cache
+.stylelintcache
+
+# Optional REPL history
+.node_repl_history
+
+# Output of 'npm pack'
+*.tgz
+
+# Yarn Integrity file
+.yarn-integrity
+
+# dotenv environment variable files
+.env
+.env.*
+!.env.example
+
+# parcel-bundler cache (https://parceljs.org/)
+.cache
+.parcel-cache
+
+# Next.js build output
+.next
+out
+
+# Nuxt.js build / generate output
+.nuxt
+dist
+.output
+
+# Gatsby files
+.cache/
+# Comment in the public line in if your project uses Gatsby and not Next.js
+# https://nextjs.org/blog/next-9-1#public-directory-support
+# public
+
+# vuepress build output
+.vuepress/dist
+
+# vuepress v2.x temp directory
+.temp
+
+# Sveltekit cache directory
+.svelte-kit/
+
+# vitepress build output
+**/.vitepress/dist
+
+# vitepress cache directory
+**/.vitepress/cache
+
+# Docusaurus cache and generated files
+.docusaurus
+
+# Serverless directories
+.serverless/
+
+# FuseBox cache
+.fusebox/
+
+# DynamoDB Local files
+.dynamodb/
+
+# Firebase cache directory
+.firebase/
+
+# TernJS port file
+.tern-port
+
+# Stores VSCode versions used for testing VSCode extensions
+.vscode-test
+
+# pnpm
+.pnpm-store
+
+# yarn v3
+.pnp.*
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/sdks
+!.yarn/versions
+
+# Vite files
+vite.config.js.timestamp-*
+vite.config.ts.timestamp-*
+.vite/
+
+saves/
+bugs.md
+DESIGN.md
diff --git a/chapter3/README.md b/detective-game/README.md
similarity index 100%
rename from chapter3/README.md
rename to detective-game/README.md
diff --git a/chapter3/casegen/accusation.js b/detective-game/casegen/accusation.js
similarity index 100%
rename from chapter3/casegen/accusation.js
rename to detective-game/casegen/accusation.js
diff --git a/chapter3/casegen/anonymous_letter.js b/detective-game/casegen/anonymous_letter.js
similarity index 100%
rename from chapter3/casegen/anonymous_letter.js
rename to detective-game/casegen/anonymous_letter.js
diff --git a/chapter3/casegen/citizens.js b/detective-game/casegen/citizens.js
similarity index 100%
rename from chapter3/casegen/citizens.js
rename to detective-game/casegen/citizens.js
diff --git a/chapter3/casegen/constants.js b/detective-game/casegen/constants.js
similarity index 100%
rename from chapter3/casegen/constants.js
rename to detective-game/casegen/constants.js
diff --git a/chapter3/casegen/devices.js b/detective-game/casegen/devices.js
similarity index 100%
rename from chapter3/casegen/devices.js
rename to detective-game/casegen/devices.js
diff --git a/chapter3/casegen/district.js b/detective-game/casegen/district.js
similarity index 100%
rename from chapter3/casegen/district.js
rename to detective-game/casegen/district.js
diff --git a/chapter3/casegen/evening.js b/detective-game/casegen/evening.js
similarity index 100%
rename from chapter3/casegen/evening.js
rename to detective-game/casegen/evening.js
diff --git a/chapter3/casegen/index.js b/detective-game/casegen/index.js
similarity index 97%
rename from chapter3/casegen/index.js
rename to detective-game/casegen/index.js
index 55c536e..dc603ee 100644
--- a/chapter3/casegen/index.js
+++ b/detective-game/casegen/index.js
@@ -3,6 +3,7 @@
 // граф доказів (спланований від розв'язку назад), хибні сліди (кожен — спростовний),
 // шифро-завдання. solve() — симулятор досяжності для fair-play тестів.
 
+const crypto = require('crypto');
 const { makeDistrict, unitBuilding } = require('./district');
 const N = require('./names');
 const { hashSeed, mulberry32, ri, estRange, pick, chance, shuffle, UKR, caesar, b64, md5, translit, COMMON_PASSWORDS, genPassword } = require('./rng');
@@ -32,6 +33,10 @@ const { applyDoppelganger } = require('./mutators');
 const { generateAnonymousLetter } = require('./anonymous_letter');
 
 // ---------- Генерація справи ----------
+// Код кімнати (сесія) → сід справи. Хешуємо, щоб близькі коди («ABC», «ABC1»)
+// давали геть різні справи. Єдине джерело правди: і сервер, і тести сіють цим.
+function caseSeed(code) { return crypto.createHash('sha512').update(String(code)).digest('hex'); }
+
 function generateCase(seed) {
   const r = mulberry32(hashSeed(seed));
   const district = makeDistrict(r);
@@ -625,7 +630,7 @@ function generateCase(seed) {
     id: 'lab_print_match', side: 'analyst', at: { type: 'lab' }, requires: ['ev_weapon'],
     title: 'Повний відбиток зі знаряддя', tag: 'вбивця',
     detail: `Відбиток зі знаряддя порівняно з базою (звузьте кандидатів і зіставте вручну). Збіг за ${ri(r, 12, 16)} точками: ${killer.name}.`,
-    gives: { confirms: true }
+    gives: { confirms: true, pointsTo: killer.id } // чіткий доказ: годиться і в звинувачення, і на ордер
   });
   if (!(caseType === 'murder' && mutator === 'gloves')) add({
     id: 'lab_dna_match', side: 'analyst', at: { type: 'lab' }, requires: ['sf_dna'], special: 'dna',
@@ -634,7 +639,9 @@ function generateCase(seed) {
       ? `Електрофорез (${dnaDesc}): повний збіг доріжок — ${accomplice.name}. Дивно: на кого вказують взуття і тканина — це ІНША людина.`
       : `Електрофорез (${dnaDesc}): повний збіг доріжок — ${killer.name}.`) +
       ' Коли і чому ДНК потрапила на місце — аналіз не скаже.',
-    gives: mutator === 'accomplice' ? { pointsTo: accomplice.id } : { confirms: true }
+    // accomplice: ДНК належить спільнику → вказує на нього (твіст лишаємо).
+    // інакше збіг прямо називає вбивцю → чіткий доказ: і в звинувачення, і на ордер.
+    gives: mutator === 'accomplice' ? { pointsTo: accomplice.id } : { confirms: true, pointsTo: killer.id }
   });
   if (dna2) add({
     id: 'lab_dna_match2', side: 'analyst', at: { type: 'lab' }, requires: ['sf_dna2'], special: 'dna2',
@@ -692,6 +699,12 @@ function generateCase(seed) {
         `${mutator === 'gloves' ? 'повний відбиток зі знаряддя' : 'ДНК з місця'} і камера, що впіймала зріст. База мешканців зробила решту. Справу закрито.`
     };
 
+  // Мотив у прямій мові + монетка 50/50: чи проговорить вбивця мотив на зізнанні
+  // (для реалізму). Draw ОСТАННІЙ у генерації — після нього r не чіпаємо, тож
+  // наявні сейви лишаються тією ж справою, лише з новими полями фіналу.
+  finale.recapWhy = recapWhy;
+  finale.revealsMotive = chance(r, 0.5);
+
   // admit — пряма мова хибного підозрюваного (див. FM_KINDS), а не третьоособовий
   // зворот: цитуємо, а не вклеюємо в речення.
   finale.recap += ` ${herring.first} визна${g(herring, 'в', 'ла')}: «${fm.admit}» — та до злочину стосунку не ${g(herring, 'мав', 'мала')}.`;
@@ -712,4 +725,4 @@ function generateCase(seed) {
   };
 }
 
-module.exports = { generateCase, solve, checkAccusation, caesar, md5, translit, COMMON_PASSWORDS };
+module.exports = { generateCase, caseSeed, solve, checkAccusation, caesar, md5, translit, COMMON_PASSWORDS };
diff --git a/chapter3/casegen/junk.js b/detective-game/casegen/junk.js
similarity index 100%
rename from chapter3/casegen/junk.js
rename to detective-game/casegen/junk.js
diff --git a/chapter3/casegen/motives/blackmail.js b/detective-game/casegen/motives/blackmail.js
similarity index 100%
rename from chapter3/casegen/motives/blackmail.js
rename to detective-game/casegen/motives/blackmail.js
diff --git a/chapter3/casegen/motives/business.js b/detective-game/casegen/motives/business.js
similarity index 100%
rename from chapter3/casegen/motives/business.js
rename to detective-game/casegen/motives/business.js
diff --git a/chapter3/casegen/motives/debt.js b/detective-game/casegen/motives/debt.js
similarity index 100%
rename from chapter3/casegen/motives/debt.js
rename to detective-game/casegen/motives/debt.js
diff --git a/chapter3/casegen/motives/inherit.js b/detective-game/casegen/motives/inherit.js
similarity index 100%
rename from chapter3/casegen/motives/inherit.js
rename to detective-game/casegen/motives/inherit.js
diff --git a/chapter3/casegen/motives/jealousy.js b/detective-game/casegen/motives/jealousy.js
similarity index 100%
rename from chapter3/casegen/motives/jealousy.js
rename to detective-game/casegen/motives/jealousy.js
diff --git a/chapter3/casegen/motives/kidnap_debt.js b/detective-game/casegen/motives/kidnap_debt.js
similarity index 100%
rename from chapter3/casegen/motives/kidnap_debt.js
rename to detective-game/casegen/motives/kidnap_debt.js
diff --git a/chapter3/casegen/motives/kidnap_obsession.js b/detective-game/casegen/motives/kidnap_obsession.js
similarity index 100%
rename from chapter3/casegen/motives/kidnap_obsession.js
rename to detective-game/casegen/motives/kidnap_obsession.js
diff --git a/chapter3/casegen/motives/kidnap_ransom.js b/detective-game/casegen/motives/kidnap_ransom.js
similarity index 100%
rename from chapter3/casegen/motives/kidnap_ransom.js
rename to detective-game/casegen/motives/kidnap_ransom.js
diff --git a/chapter3/casegen/motives/mistaken.js b/detective-game/casegen/motives/mistaken.js
similarity index 100%
rename from chapter3/casegen/motives/mistaken.js
rename to detective-game/casegen/motives/mistaken.js
diff --git a/chapter3/casegen/motives/oldcrime.js b/detective-game/casegen/motives/oldcrime.js
similarity index 100%
rename from chapter3/casegen/motives/oldcrime.js
rename to detective-game/casegen/motives/oldcrime.js
diff --git a/chapter3/casegen/motives/ransom.js b/detective-game/casegen/motives/ransom.js
similarity index 100%
rename from chapter3/casegen/motives/ransom.js
rename to detective-game/casegen/motives/ransom.js
diff --git a/chapter3/casegen/motives/serial.js b/detective-game/casegen/motives/serial.js
similarity index 100%
rename from chapter3/casegen/motives/serial.js
rename to detective-game/casegen/motives/serial.js
diff --git a/chapter3/casegen/motives/stalker.js b/detective-game/casegen/motives/stalker.js
similarity index 100%
rename from chapter3/casegen/motives/stalker.js
rename to detective-game/casegen/motives/stalker.js
diff --git a/chapter3/casegen/motives/witness.js b/detective-game/casegen/motives/witness.js
similarity index 100%
rename from chapter3/casegen/motives/witness.js
rename to detective-game/casegen/motives/witness.js
diff --git a/chapter3/casegen/mutators.js b/detective-game/casegen/mutators.js
similarity index 100%
rename from chapter3/casegen/mutators.js
rename to detective-game/casegen/mutators.js
diff --git a/chapter3/casegen/names.js b/detective-game/casegen/names.js
similarity index 100%
rename from chapter3/casegen/names.js
rename to detective-game/casegen/names.js
diff --git a/chapter3/casegen/rng.js b/detective-game/casegen/rng.js
similarity index 100%
rename from chapter3/casegen/rng.js
rename to detective-game/casegen/rng.js
diff --git a/chapter3/casegen/runtime.js b/detective-game/casegen/runtime.js
similarity index 100%
rename from chapter3/casegen/runtime.js
rename to detective-game/casegen/runtime.js
diff --git a/chapter3/casegen/test.js b/detective-game/casegen/test.js
similarity index 100%
rename from chapter3/casegen/test.js
rename to detective-game/casegen/test.js
diff --git a/chapter3/package-lock.json b/detective-game/package-lock.json
similarity index 100%
rename from chapter3/package-lock.json
rename to detective-game/package-lock.json
diff --git a/chapter3/package.json b/detective-game/package.json
similarity index 100%
rename from chapter3/package.json
rename to detective-game/package.json
diff --git a/chapter3/public/analyst.js b/detective-game/public/analyst.js
similarity index 96%
rename from chapter3/public/analyst.js
rename to detective-game/public/analyst.js
index a69f7bf..427cf66 100644
--- a/chapter3/public/analyst.js
+++ b/detective-game/public/analyst.js
@@ -267,14 +267,24 @@
     if (!claims.length) { box.innerHTML = 'Ще нікого не питали, де він був того вечора.'; box.className = 'small dim'; return; }
     box.className = '';
     const bn = id => { const b = App.init.district.buildings.find(x => x.id === id); return b ? b.name.split(',')[0] : id; };
-    const t = el('table', '', '<tr><th>Хто</th><th>Каже, що був</th><th>Камери над тим місцем</th></tr>');
+    const t = el('table', '', '<tr><th>Хто</th><th>Каже, що був</th><th>Камери над тим місцем</th><th></th></tr>');
     for (const [cid, claim] of claims) {
       const c = App.byId(cid);
-      const cams = App.init.district.cameras.filter(cam => cam.covers.includes(claim));
+      // Той самий ключ, що й у базі мешканців: галочка/викреслення на особі — спільні.
+      const key = 'c:' + cid;
+      if (App.state.board.marks[key] === 'hide') continue; // сховане в базі — сховане й тут
+      // Зізнався, що збрехав → показуємо перехід «стара заява → реальне місце»,
+      // і камери підтягуємо вже над реальним місцем (обидві колонки синхронно).
+      const real = (App.state.alibiReal || {})[cid];
+      const place = real || claim;
+      const said = real ? `${esc(bn(claim))} → ${esc(bn(real))}` : esc(bn(claim));
+      const cams = App.init.district.cameras.filter(cam => cam.covers.includes(place));
       const cell = cams.length
         ? cams.map(cam => `${esc(cam.name)}${(App.state.cctvPulled || []).includes(cam.id) ? ' — архів на дошці' : ' — архів не тягнули'}`).join('<br>')
         : 'жодна камера туди не дивиться';
-      t.append(el('tr', '', `<td>${esc(c.name)}</td><td>${esc(bn(claim))}</td><td class="small">${cell}</td>`));
+      const tr = el('tr', cardClasses(key), `<td>${esc(c.name)}</td><td>${said}</td><td class="small">${cell}</td>`);
+      const mk = el('td'); mk.append(markButtons(key)); tr.append(mk);
+      t.append(tr);
     }
     box.innerHTML = ''; box.append(t);
   }
diff --git a/chapter3/public/client.js b/detective-game/public/client.js
similarity index 94%
rename from chapter3/public/client.js
rename to detective-game/public/client.js
index 420534a..ae31fba 100644
--- a/chapter3/public/client.js
+++ b/detective-game/public/client.js
@@ -178,6 +178,23 @@ function cardClasses(key) {
   return m && m !== "hide" ? " " + m : "";
 }
 
+// Прокрутити дошку до доказу за id і коротко підсвітити. Якщо він у згорнутій
+// секції «Приховані» — спершу розгортаємо її й перемальовуємо.
+function jumpToEvidence(id) {
+  const find = () =>
+    document.querySelector(`#sidebody [data-ev="${CSS.escape(id)}"]`);
+  let card = find();
+  if (!card && !showHidden) {
+    showHidden = true;
+    renderSide();
+    card = find();
+  }
+  if (!card) return;
+  card.scrollIntoView({ behavior: "smooth", block: "center" });
+  card.classList.add("flash");
+  setTimeout(() => card.classList.remove("flash"), 1300);
+}
+
 function renderSide() {
   if (!App.state) return;
   const body = $("#sidebody");
@@ -211,6 +228,7 @@ function renderSide() {
     const buildCard = (e) => {
       const key = "e:" + e.id;
       const c = el("div", "card" + cardClasses(key));
+      c.dataset.ev = e.id; // якір для прокрутки-до-доказу
       const t = el("div", "t");
       t.append(el("b", "", esc(e.title)));
       const pin = el(
@@ -220,7 +238,17 @@ function renderSide() {
       );
       pin.onclick = () => App.send({ t: "pin", evId: e.id });
       t.append(pin);
-      c.append(t, el("div", "small", esc(e.detail)), markButtons(key));
+      c.append(t, el("div", "small", esc(e.detail)));
+      // Експертиза називає доказ, який розбирала, і веде до нього (прокрутка + підсвітка).
+      if (e.ref) {
+        const src = found.find((x) => x.id === e.ref);
+        if (src) {
+          const link = el("button", "evref small", `↳ аналіз доказу: «${esc(src.title)}»`);
+          link.onclick = () => jumpToEvidence(e.ref);
+          c.append(link);
+        }
+      }
+      c.append(markButtons(key));
       const notes = (App.state.board.enotes || {})[e.id] || [];
       for (const n of notes) {
         const row = el(
diff --git a/chapter3/public/field.js b/detective-game/public/field.js
similarity index 98%
rename from chapter3/public/field.js
rename to detective-game/public/field.js
index 3be7ac6..f2012d6 100644
--- a/chapter3/public/field.js
+++ b/detective-game/public/field.js
@@ -2,6 +2,7 @@
 "use strict";
 (() => {
   let cv, ctx, hint;
+  let started = false; // слухачі/цикл/розсилку ставимо раз, навіть якщо init прийде знову
   let player = { x: 85, y: 290 };
   const keys = {};
   let solids = [],
@@ -168,11 +169,16 @@
     stage.append(cv, hint);
     ctx = cv.getContext("2d");
     fitCanvas(cv);
-    addEventListener("resize", () => fitCanvas(cv));
     solids = m.district.buildings
       .filter((b) => !OPEN_ZONES.includes(b.id))
       .map((b) => b.pos);
     walkIn = m.district.buildings.filter((b) => OPEN_ZONES.includes(b.id));
+    // init прилітає й на реконекті: канвас/стан перебудували вище, а глобальні
+    // слухачі, цикл рендеру й розсилку позицій ставимо ЛИШЕ раз — інакше після
+    // кожного реконекту крутився б зайвий loop і дублювались клавіші.
+    if (started) return;
+    started = true;
+    addEventListener("resize", () => fitCanvas(cv));
     // e.code — фізична клавіша, працює на будь-якій розкладці (укр/лат)
     addEventListener("keydown", (e) => {
       if (e.target.tagName === "INPUT" || e.target.tagName === "TEXTAREA")
diff --git a/chapter3/public/index.html b/detective-game/public/index.html
similarity index 98%
rename from chapter3/public/index.html
rename to detective-game/public/index.html
index 114e149..ba54b03 100644
--- a/chapter3/public/index.html
+++ b/detective-game/public/index.html
@@ -89,6 +89,9 @@
   #side .tag { font-size:10.5px; background:transparent; border:1px solid #b3a077; color:var(--inkdim); border-radius:2px; padding:0 5px; }
   .card .t { display:flex; gap:6px; align-items:baseline; }
   .card .t b { flex:1; }
+  .evref { display:block; width:100%; text-align:left; margin-top:4px; font-style:italic; }
+  @keyframes evflash { 0%,100% { box-shadow:0 4px 10px rgba(0,0,0,.55); } 25%,60% { box-shadow:0 0 0 3px var(--acc), 0 4px 14px rgba(0,0,0,.6); } }
+  #side .card.flash { animation:evflash 1.3s ease; }
   .mk { display:flex; gap:4px; margin-top:6px; }
   .mk button { padding:1px 8px; font-size:12px; }
   .mk button.on { border-color:#7a1f1f; color:#7a1f1f; font-weight:bold; }
diff --git a/chapter3/public/sound.js b/detective-game/public/sound.js
similarity index 100%
rename from chapter3/public/sound.js
rename to detective-game/public/sound.js
diff --git a/chapter3/server.js b/detective-game/server.js
similarity index 92%
rename from chapter3/server.js
rename to detective-game/server.js
index 2791ccd..eab50fc 100644
--- a/chapter3/server.js
+++ b/detective-game/server.js
@@ -4,9 +4,8 @@ const http = require('http');
 const fs = require('fs');
 const path = require('path');
 const os = require('os');
-const crypto = require('crypto');
 const { WebSocketServer } = require('ws');
-const { generateCase, checkAccusation, md5 } = require('./casegen');
+const { generateCase, caseSeed, checkAccusation, md5 } = require('./casegen');
 const { unitBuilding } = require('./casegen/district');
 const RT = require('./casegen/runtime');
 
@@ -40,7 +39,7 @@ function seedRand(seed) {
 
 function getSession(code) {
   if (sessions[code]) return sessions[code];
-  const hashedCode = crypto.createHash('sha512').update(code).digest('hex');
+  const hashedCode = caseSeed(code);
   const cs = generateCase(hashedCode);
   const rng = seedRand([...hashedCode].reduce((a, c) => a * 31 + c.charCodeAt(0), 0));
   const stn = cs.district.buildings.find(b => b.id === 'station');
@@ -131,7 +130,11 @@ function view(s) {
   const { cs, st } = s;
   const found = st.found.map(id => {
     const ev = cs.evidence[id];
-    return { id, title: ev.title, detail: ev.detail, side: ev.side };
+    const card = { id, title: ev.title, detail: ev.detail, side: ev.side };
+    // Експертиза (crim/expert) розбирає конкретний доказ — його id у requires[0].
+    // Віддаємо як ref, щоб на дошці було видно, ЧИЙ це аналіз, і клік вів до нього.
+    if (ev.q && ev.q.kind === 'expert' && ev.requires[0]) card.ref = ev.requires[0];
+    return card;
   }).concat(s.extra);
   const killerC = cs.citizens.find(c => c.id === cs.finale.killer);
   const dnaOwner = cs.citizens.find(c => c.id === (cs.accomplice || cs.finale.killer));
@@ -143,6 +146,12 @@ function view(s) {
     puzzles: visiblePuzzles(s),
     locs: s.locs, markers: s.markers, log: s.log,
     alibiClaims: s.alibiClaims,
+    // Хто вже зізнався, що збрехав про вечір → його СПРАВЖНЄ місце (c.evening).
+    // Клієнт правди не має (evening вирізано в pubCitizens), тож віддаємо тут —
+    // тільки для розколотих, тож нічого понад уже сказане в зізнанні не тече.
+    alibiReal: Object.fromEntries(Object.keys(s.alibiClaims)
+      .filter(cid => s.cracked[cid])
+      .map(cid => [cid, byIdC(cs, cid).evening])),
     cctvPulled: s.extra.filter(x => x.key && x.key.startsWith('cctv|')).map(x => x.key.slice(5)),
     dnaSample: st.found.includes('sf_dna') ? dnaOwner.dna : null,
     dnaLabel: st.found.includes('sf_dna') ? cs.dnaDesc : null,
@@ -565,8 +574,19 @@ function handle(s, ws, m) {
           `${c.name} впізнає слід біля місця злочину: ${g(c, 'проходив', 'проходила')} там того вечора. До справи відношення не має.`);
       } else if (K && gives.confirms) {
         a = `Довга пауза. «...Гаразд. Ваша взяла.» — і ${c.name} починає говорити.`;
+        // Зізнання підтверджує ХТО/ЯК, але мотив цим не доводиться: прокурор вимагає
+        // ЗАКРІПЛЕНИЙ доказ мотиву (accusation.js). Тож картка чесно каже, що ЧОМУ —
+        // ще відкрите, інакше гравець думає, що вже все, і зависає на звинуваченні.
+        const motiveBacked = st.found.some(id => cs.evidence[id] && cs.evidence[id].gives && cs.evidence[id].gives.motive);
+        const whyLine = motiveBacked
+          ? `Мотив уже підкріплено доказом. Лишилося оформити справу: ХТО / ЯК / ЧОМУ і закріпити докази для прокурора.`
+          // 50/50 (вирішено при генерації справи): інколи вбивця сам проговорює мотив.
+          // Але слова — ще не доказ: прокурор усе одно вимагає ЗАКРІПЛЕНИЙ доказ мотиву.
+          : cs.finale.revealsMotive && cs.finale.recapWhy
+            ? `Цього разу ${g(c, 'він заговорив', 'вона заговорила')} і про мотив: ${cs.finale.recapWhy} Та зізнання на словах — ще не доказ: щоб оформити ЧОМУ, знайдіть і закріпіть доказ мотиву.`
+            : `Але про мотив мовчить: ЧОМУ ще не доведено. Прокурор не прийме справу без ЗАКРІПЛЕНОГО доказу мотиву — знайдіть і закріпіть його, тоді оформлюйте ХТО / ЯК / ЧОМУ.`;
         extraCard(s, 'confess', `Зізнання: ${c.name}`,
-          `Після пред'явлення (${ev.title.toLowerCase()}) ${c.name} ${g(c, 'зізнався', 'зізналася')}. Протокол підписано. Лишилося оформити справу: ХТО / ЯК / ЧОМУ — і закріпити докази для прокурора.`);
+          `Після пред'явлення (${ev.title.toLowerCase()}) ${c.name} ${g(c, 'зізнався', 'зізналася')} у скоєному. Протокол підписано. ${whyLine}`);
       } else if (cs.dna2 && c.id === cs.dna2.owner && ['sf_dna2', 'lab_dna_match2'].includes(m.evId)) {
         // невинна ДНК: людина пояснює, звідки вона там, — вірити чи ні, вирішують гравці
         const vic = byIdC(cs, cs.victim);
@@ -751,8 +771,23 @@ function pubCitizens(cs) {
 }
 
 const wss = new WebSocketServer({ server });
+// Heartbeat: без нього обірване з'єднання (сон ноута, зміна Wi-Fi, kill) лишає
+// мертвий сокет у s.clients назавжди — застигла точка на мапі, «Польовий2» за
+// одного гравця, роздутий лічильник. Пінгуємо всіх; хто не відповів між тіками —
+// terminate, і штатний 'close' прибирає його з сесії.
+const HEARTBEAT_MS = +process.env.HEARTBEAT_MS || 30000;
+const heartbeat = setInterval(() => {
+  for (const ws of wss.clients) {
+    if (ws.isAlive === false) { ws.terminate(); continue; }
+    ws.isAlive = false;
+    try { ws.ping(); } catch { }
+  }
+}, HEARTBEAT_MS);
+wss.on('close', () => clearInterval(heartbeat));
 wss.on('connection', ws => {
   ws.id = ++clientSeq;
+  ws.isAlive = true;
+  ws.on('pong', () => { ws.isAlive = true; });
   ws.on('message', raw => {
     let m; try { m = JSON.parse(raw); } catch { return; }
     if (m.t === 'join') {
diff --git a/chapter3/test-server.js b/detective-game/test-server.js
similarity index 98%
rename from chapter3/test-server.js
rename to detective-game/test-server.js
index 8e59f6a..bdec899 100644
--- a/chapter3/test-server.js
+++ b/detective-game/test-server.js
@@ -5,7 +5,7 @@ const fs = require('fs');
 const path = require('path');
 const { spawn } = require('child_process');
 const WebSocket = require('ws');
-const { generateCase } = require('./casegen');
+const { generateCase, caseSeed } = require('./casegen');
 
 const PORT = +process.env.PORT || 3102;
 const NO_SPAWN = !!process.env.NO_SPAWN; // підключитись до вже запущеного сервера (для дебагу з логами)
@@ -43,7 +43,7 @@ function solveTriangulate(cs, towers) {
 }
 
 async function playToTheEnd(session, accusation) {
-  const cs = generateCase(session);
+  const cs = generateCase(caseSeed(session)); // сервер сіє хешованим кодом — тест мусить так само
   const killer = cs.citizens.find(c => c.id === cs.finale.killer);
   const field = client('field'); field.session = session;
   const analyst = client('analyst'); analyst.session = session;