---
key: mechanic/stealth-infiltration--t032
type: mechanic
id: stealth-infiltration--t032
lang: en
title: 'Suspicion, alerts and searching'
summary: >-
  Suspicion moves observers from routine behavior through investigation, alerts
  and searching for a last known target.
updatedAt: '2026-10-22'
status: active
url: 'https://gamemechanics.pro/en/knowledge/mechanic/stealth-infiltration--t032/'
jsonUrl: >-
  https://gamemechanics.pro/api/v1/knowledge/en/mechanic/stealth-infiltration--t032.json
markdownUrl: >-
  https://gamemechanics.pro/content/knowledge/en/mechanic/stealth-infiltration--t032.md
aliases: []
tags:
  - 'Stealth, infiltration and escape'
  - Mechanics and variants
sourceIds:
  - source-3817d420df0baa92
  - source-f3ed8d6e91e4574f
sources:
  - id: source-3817d420df0baa92
    title: 'Robert Nystrom: State'
    url: >-
      https://github.com/munificent/game-programming-patterns/blob/master/book/state.markdown
    verifiedAt: null
  - id: source-f3ed8d6e91e4574f
    title: Deus Ex
    url: 'https://gamemechanics.org/patterns/surveillance-cameras'
    verifiedAt: null
relations:
  - type: uses
    direction: outgoing
    label: Sources in the selection
    key: resource/state-pattern
    title: 'State: Game Programming Patterns'
    url: 'https://gamemechanics.pro/en/resources/#resource-state-pattern'
    jsonUrl: 'https://gamemechanics.pro/api/v1/knowledge/en/resource/state-pattern.json'
    markdownUrl: 'https://gamemechanics.pro/content/knowledge/en/resource/state-pattern.md'
placements:
  - catalogId: stealth-infiltration
    id: t032
    title: 'Stealth, infiltration and escape'
    url: 'https://gamemechanics.pro/en/mechanics/stealth-infiltration/#t032'
    categoryIds:
      - mechanics
supersededBy: []
attributes:
  preview:
    updatedAt: '2026-10-22'
    title: 'Suspicion, alerts and searching'
    description: >-
      Suspicion moves observers from routine behavior through investigation,
      alerts and searching for a last known target.
    image:
      src: images/mechanics/interaction-surveillance-cameras.webp
      width: 900
      height: 499
      game: Deus Ex
      sourceUrl: 'https://gamemechanics.org/patterns/surveillance-cameras'
      originalUrl: 'https://cdn.gamemechanics.org/deus_ex_surveillance_camera.jpg'
      credit: Ion Storm; image via GameMechanics.org
      rights: >-
        Game imagery © its respective rights holders. Source host:
        GameMechanics.org. Visible source watermarks preserved. All rights
        reserved; excluded from MIT and CC BY 4.0.
      caption: A camera above a door watches the approach
      alt: A camera with a green indicator is mounted above a passage in Deus Ex.
      markers:
        - x: 54
          'y': 28
          label: Camera lens above the passage
        - x: 50
          'y': 73
          label: Watched route beside the door
    tips:
      - >-
        Distinguish a noticed signal, confirmed alarm and search of the last
        known position.
    examples:
      - title: Deus Ex
        url: 'https://gamemechanics.org/patterns/surveillance-cameras'
endsAt: null
provenance: >-
  Original bilingual editorial overviews authored for gamemechanics.pro on
  2026-10-20 and reviewed on 2026-10-21. Scenarios are hypothetical design
  examples; prototype checks describe work to perform, not completed playtests.
  Primary sources support the stated techniques and implementation context, not
  every proposed variant.
license: CC-BY-4.0
codeLicense: MIT
attribution: gamemechanics.pro contributors
catalogKey: catalog/stealth-infiltration
---
# Suspicion, alerts and searching

id: stealth-infiltration--t032
type: mechanic
key: mechanic/stealth-infiltration--t032
lang: en
status: active
url: https://gamemechanics.pro/en/knowledge/mechanic/stealth-infiltration--t032/

Suspicion moves observers from routine behavior through investigation, alerts and searching for a last known target.

## At a glance

![A camera with a green indicator is mounted above a passage in Deus Ex.](https://gamemechanics.pro/images/mechanics/interaction-surveillance-cameras.webp)

[Deus Ex](https://gamemechanics.org/patterns/surveillance-cameras) · Game imagery © its respective rights holders. Source host: GameMechanics.org. Visible source watermarks preserved. All rights reserved; excluded from MIT and CC BY 4.0.

1. Camera lens above the passage
2. Watched route beside the door

- Distinguish a noticed signal, confirmed alarm and search of the last known position.

- [Deus Ex](https://gamemechanics.org/patterns/surveillance-cameras)

## How it works

Suspicion moves observers from routine behavior through investigation, alerts and searching for a last known target.

## Variants

### Mechanic variants

<a id="t032-variants"></a>

- Investigation approaches an unusual signal source. <a id="t032-v1"></a>
- Alerts spread through available communication channels. <a id="t032-v2"></a>
- Search expands from the last known contact. <a id="t032-v3"></a>
- Returning to routine preserves memory of a threat. <a id="t032-v4"></a>

## Design example

A guard investigates an open door, calls a partner and then searches nearby rooms.

Prototype check: Test that a searching guard cannot obtain the hidden player's exact position without observing a new signal.

## Context and limits

Stealth manages what observers know through visibility, suspicion, traces, decoys and escape routes. Each overview separates player actions, state changes and alternative rules. Examples are hypothetical design scenarios, not claims about a named game. A prototype check states an observable question for the next iteration. Existing detailed references remain separately linked from the direction map.

## Connected materials

- Sources in the selection: [State: Game Programming Patterns](https://gamemechanics.pro/en/resources/#resource-state-pattern) (key: resource/state-pattern)

## Sources and provenance

Original bilingual editorial overviews authored for gamemechanics.pro on 2026-10-20 and reviewed on 2026-10-21. Scenarios are hypothetical design examples; prototype checks describe work to perform, not completed playtests. Primary sources support the stated techniques and implementation context, not every proposed variant.

- [Robert Nystrom: State](https://github.com/munificent/game-programming-patterns/blob/master/book/state.markdown) (id: source-3817d420df0baa92)
- [Deus Ex](https://gamemechanics.org/patterns/surveillance-cameras) (id: source-f3ed8d6e91e4574f)

CC-BY-4.0 · gamemechanics.pro contributors