> ## Documentation Index
> Fetch the complete documentation index at: https://docs.cadmus-cad.app/llms.txt
> Use this file to discover all available pages before exploring further.

# Evidence capture

> This guide explains how to capture, view, and manage evidence photos in the Cadmus MDT app.

This guide explains how to capture, view, and manage evidence photos in the Cadmus MDT app.

## Overview

Evidence capture lets officers take photos tied to specific incidents. Each photo is tagged with:

* **Incident** — Call number and incident ID
* **Unit** — Your assigned unit
* **Officer** — Your name and badge number
* **Location** — GPS coordinates (when available)
* **Time** — Capture timestamp (UTC)

Photos are stored only in the app's private storage. They are **not** saved to the device photo gallery.

## Capturing evidence

<Steps>
  <Step title="Open the camera">
    From the **Calls** screen, when you're assigned to a call, tap the **camera icon** (Capture evidence photo). The camera opens in full screen with the back camera.
  </Step>

  <Step title="Take a photo">
    Point the camera at the scene and tap the **capture button** (large circle). The app shows a preview of the captured image.
  </Step>

  <Step title="Save or retake">
    Tap **Save** to store the photo and return to the call (you'll see "Evidence photo saved"), or **Retake** to discard and shoot again.
  </Step>
</Steps>

### Requirements

* You must be **logged in** to save evidence.
* You must be **assigned to the call** to capture evidence for that incident.

## Viewing evidence

### Gallery

* Open the **Evidence** section from the app navigation.
* Photos are grouped by **incident** (call number).

### Opening an incident

* Tap an incident card to open its photo grid.
* Photos are shown newest first.

### Viewing a single photo

* Tap a photo to open it full screen.
* A **metadata panel** shows call number, unit, officer, date/time, GPS, and SHA-256 hash.
* Tap **X** or swipe back to close.

## Deleting photos

* In the incident photo grid, open a photo and use **delete**.
* Deletion is recorded in the audit log.

## Offline use

* **Capture** and **view** work offline.
* If GPS is unavailable, coordinates may show as 0,0 — the photo is still saved.
* You must be logged in to save while offline.

## Error messages

| Message                              | Meaning                                                         |
| ------------------------------------ | --------------------------------------------------------------- |
| No cameras available                 | Device has no usable camera.                                    |
| Failed to initialize camera          | Camera could not start. Close other apps or restart the device. |
| Not logged in. Cannot save evidence. | Log in before saving photos.                                    |
| Failed to save                       | Storage or system error. Try again.                             |
| Photo not found                      | Photo may have been deleted or data was cleared.                |

## Tips

* Capture photos as soon as possible after arriving on scene.
* Ensure good lighting and a clear view of the subject.
* Use **Retake** if the image is blurry or poorly framed.
* Check the metadata panel to confirm location and timestamp for reports.

<Warning>
  Evidence photos are stored in the app's private storage only — not the device gallery. Follow agency policy for chain of custody and authorized disclosure.
</Warning>