Crime Scene Preservation

The Guard's Role at a Crime Scene

A security guard is often the first person on scene at a theft, assault, break-in, or disturbance. What the guard does in the first minutes frequently determines whether the Crown can build a case. The guard's role is narrow but critical: preserve the scene and its evidence for police — do not investigate the offence.

Investigation — interviewing suspects, collecting forensic samples, reconstructing the event — is the job of the police. A guard who tries to investigate risks contaminating evidence, tainting witness recollections, and exceeding lawful authority.

The Priority Hierarchy: Life First

Everything a guard does at a scene follows a fixed order of priorities:

1. Protect life — your own, the victim's, and the public's. Render first aid, call for medical help, and remove people from danger before anything else.
2. Preserve the scene — once life-safety issues are handled, take steps to keep the scene unchanged.
3. Protect evidence — within the preserved scene, shield specific items from weather, movement, and contamination.

Life always comes first. If you must move a victim or a piece of furniture to reach an injured person, do so — but note what you moved, why, and where, so the change is documented rather than mistaken for part of the original scene.

The Scene-Response Sequence

The following diagram shows the recommended sequence of actions from arrival to handover. Steps may overlap (you may call police while securing the area), but the order of priorities does not change.

flowchart TD
    A[Arrive on scene] --> B{Is anyone injured or in danger?}
    B -- Yes --> C[Render first aid / call medical]
    B -- No --> D[Secure and isolate the area]
    C --> D
    D --> E[Control entry and exit - log who comes and goes]
    E --> F[Do not touch or move evidence unless necessary]
    F --> G[Protect evidence from weather and public]
    G --> H[Record initial observations before anything changes]
    H --> I[Call or update police]
    I --> J[Turn scene over to police and brief them]

Securing and Isolating the Area

Securing the scene means establishing a boundary that keeps unauthorized people out. Depending on the setting, a guard may use:

• Physical barriers — doors, gates, rope, tape, or cones
• Verbal instructions — directing staff, customers, and bystanders away
• Posting another guard or staff member at the entrance

The boundary should be larger than the obvious scene. Expand the perimeter to include the path the suspect likely took, the location of any discarded items, and any area where witnesses were standing. It is easier to shrink a perimeter later than to recover evidence that was trampled while the boundary was too tight.

Contamination and the Entry Log

Contamination is any change to the scene or its evidence caused after the event — fingerprints added, blood smeared, footwear impressions overwritten, fibres transferred. The most common source of contamination is people: the guard, other responders, the victim, and curious onlookers.

To control contamination, maintain an entry/exit log of everyone who passes through the boundary:

• Name and role (police, EMS, manager, guard)
• Time in and time out
• Reason for entry
• What, if anything, they touched or moved

This log becomes part of the evidence. If the defence later claims a fingerprint could have been left by a responder, the log shows who was present and when.

Do Not Touch, Do Not Move, Do Not Clean

Three rules that guards violate most often:

• Do not touch evidence unless it is necessary to protect life or prevent its destruction. If you must touch it, note it.
• Do not move items to "tidy" the scene or to make room. A moved weapon or displaced chair changes the story the scene tells.
• Do not clean up — not blood, not broken glass, not scattered papers. Cleaning destroys trace evidence and alters the scene's geometry. Wait for police to release the scene.

Protect Evidence from Weather and the Public

Outdoor scenes are vulnerable to rain, wind, sun, and foot traffic. Where practicable, a guard should cover trace evidence (a discarded weapon, a footwear impression) with a box, tarp, or similar cover — without touching the evidence itself — and keep the public at a distance until police arrive.

Record Initial Observations Before They Change

Before anything is moved, before the crowd disperses, and while details are fresh, the guard should record initial observations in the notebook:

• Date, time, and location of arrival
• Who was present and their positions
• The condition of the scene — what was open, broken, disturbed, or out of place
• Weather and lighting conditions
• Anything the guard did (first aid, moving an object, securing a door)

These notes become the guard's contemporaneous record and may be used to refresh memory on the stand.

Chain of Custody

Chain of custody is the unbroken, documented record of every person who handled a piece of evidence from the moment it was collected to the moment it is presented in court. Each transfer is recorded: who collected it, when, where it was stored, who took it next, and under what seal.

Security guards rarely collect evidence in the forensic sense — that is the role of police. But a guard must understand the principle, because:

• A guard's failure to secure the scene can break the chain before it begins, making later evidence inadmissible
• A guard who moves an item and hands it to police has become the first link in the chain and must be able to testify to that handling
• A guard who cannot account for who entered the scene cannot rebut a claim that evidence was tampered with

When Police Arrive

When police take control, the guard's job shifts to briefing. Provide the responding officer with:

• The nature of the incident and what was observed on arrival
• The location and condition of any evidence or victims
• The names and statements of any witnesses still on scene
• A copy of the entry/exit log
• The guard's notebook reference for the incident

Remain available. The guard may be required to testify later, and the notebook is the foundation of that testimony.