Leave it, protect it, report it
Forensic evidence may be fragile or invisible. Restrict movement, keep people away and follow instructions from the investigating authority before cleaning, repairing or moving items.
Possible evidence
| Type | Avoid |
|---|---|
| Door, window and lock surfaces | Touching handles, frames, broken edges, latch areas or tools |
| Footwear and tyre marks | Walking, sweeping, driving or placing objects over them |
| Blood, hair or fibres | Cleaning, covering with absorbent material or handling |
| Discarded objects | Picking up gloves, tools, packaging, bottles or cigarette ends |
| Digital evidence | Editing originals, changing device time, deleting notifications or sharing clips publicly |
If weather or safety threatens evidence
Tell police immediately. If instructed to protect an item, minimise contact and document exactly what was moved, by whom, when and why. Do not improvise chemical cleaning, fingerprint powders or evidence collection.
Camera-footage preservation
- Note the camera name, location, displayed time zone and whether the clock is accurate.
- Export the relevant original-quality clip plus useful time before and after the event.
- Keep the original filename and create a separate working copy if needed.
- Record who downloaded, viewed and transferred the file.
- Do not post footage publicly while an investigation is active without police advice.
- Preserve doorbell notifications, account alerts and provider emails.
Your safety overrides scene preservation. Leave immediately if the structure, broken glass, electricity, fire, gas, offender or another hazard makes the property unsafe.
Related guidance
First-hour checklist · Police footage requests · Protect cloud evidence
Official reference: Metropolitan Police forensic-evidence guidance.
Last checked: 1 September 2026.