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SIO Corner: Exhibits And Scene Security

This week we look at the role of the Exhibits Officer and the importance of preserving and securing the scene

In this series we look at various aspects of life as an SIO. This includes the necessary skill sets for the successful SIO, the management of serious crime investigation and specific elements of investigative practice from initial response through crime scene examination and investigative strategies to dealing with suspects and the media. The articles are excerpts from the 2nd edition of Blackstone's, the 'Senior Investigating Officers' Handbook', written by two highly experienced SIOs (see 'About the Authors' at the end of the article).

Role of Exhibits Officers (EO)

An EO has a pivotal role in any investigation and should be an experienced detective or investigator trained in all aspects of exhibit management, including packaging, storage, documentation, and the HOLMES2 Exhibit Management System, together with an up-to-date knowledge of forensic techniques and their applications.

From the outset of the investigation, the EO should be identified and remain for the duration of the investigation through to the completion of any trial. They should attend all briefings and must establish a close working relationship with the CSM, CSIs, first officers responding, and indeed all the investigators, in order to ensure that all recovered exhibits are properly handled and packaged, together with the necessary signed labels.

Extreme care must be exercised to guard against the risk of contamination or cross-contamination throughout the entire exhibit handling process. The importance of preserving the integrity of an exhibit cannot be overstated. The best prosecution case can fail if there is a breakdown in continuity of a key forensic exhibit and that is a core responsibility of the EO.

The EO should be allocated a dedicated office with appropriate storage, freezer, drying facilities, and a HOLMES2 terminal. Throughout the investigation all exhibits must be kept under close review, particularly those sent for specialist forensic or fingerprint treatment or examination.

The management team should hold formal exhibit reviews on a regular basis in order to assess the forensic potential of every exhibit and check on any outstanding examination results that are awaited.

Processing a Crime Scene

The various phases of managing and processing a crime scene are as follows:

1. First response officer(s) and any other emergency services attend the scene(s)

2. Identification, security, and protection of the scene(s) takes place.

3. A crime scene assessment is conducted.

4. Detailed forensic examinations and searching take place.

5. Correct scene documentation and exhibit recovery and management procedures are applied.

6. Any relevant material (i.e. under CPIA requirements) is correctly recorded and recovered.

7. Health and safety and cross-contamination risks are carefully managed and controlled throughout 1–6 above.

Scene Security and Preservation

It must be remembered that the actions taken by the first responders at a crime scene have a huge impact on the outcome of an investigation. Destruction, contamination, or loss of evidential material is most likely to occur at this stage or very soon thereafter.

When the police are despatched to incidents or reports of suspicious circumstances there may well be other competing demands for their attention as well as the requirement to preserve evidence, e.g. violent confrontations, public disorder, casualties, distressed victims, families, friends or witnesses, environmental challenges etc.

They must nevertheless ensure that correct procedures at some point are applied in order to give the recovery of trace evidence every chance of success. The fundamental principle is that once identified and secured, crime scenes must be preserved and protected from entry by unnecessary and unauthorized persons (including the family, friends, and relatives of victims, offenders, and in particular the media).

This is to avoid physical evidence being altered, moved, destroyed, lost, or contaminated. No one should be allowed to enter a designated crime scene except to save life or certify life extinct until the arrival of a senior detective and/or the SIO and crime scene manager/investigators.

Any official persons, including supervisory personnel and senior officers, who do not have a specific or valid reason for being inside the crime scene should be regarded as unauthorized persons. Only the SIO or the crime scene manager can grant access to a crime scene, and this rule must be firmly communicated to all those involved at the scene(s).

Upon arrival at the scene, the SIO should conduct an immediate assessment of the security arrangements and parameters, position, and adequacy of the cordons. This should take cognizance of the circumstances of the case and any information that is known, such as possible routes the offenders took to and from the scene.

The exact parameters, when determined, should be both recorded in writing and indicated clearly and accurately on a sketch, plan and/or map. If any alterations are made to the parameters then these also need accurately recording.

Note: When entry into a scene is authorized by the SIO, say for a medical professional (or an expert) they should, wherever possible, be provided with suitable protective clothing, e.g. scene suit, overshoes, gloves, mask, and hood. A member of the crime scene investigation team should also accompany them.

Case study — waste bin clue

A drinks can was found in a waste bin situated marginally outside the police crime scene cordon. Because of its position, tape fastened to a nearby lamp-post at a bus stop initially excluded the bin. Fortunately the SIO reviewed and extended the cordon parameters to include the area covered by the bin.

A witness subsequently identified the offender as having stood at the bus stop before the murder was committed, drinking from a drinks can, which he was then seen to place in the waste bin. The can was forensically recovered and revealed the DNA profile of the offender.


1. The size of a cordon is important to protect and preserve evidence. A cordon that is too big can be reduced whereas a cordon that is too small cannot be enlarged so the rule is always err on the side of caution and start big.

2. In firearm discharges stray bullets can and do travel much further than a target or victim’s location. Therefore, proposed search areas for bullet heads may need to be significantly extended—a fact worth considering when setting cordon parameters.

Next week we look at issues relating to scene cordons.

About the Authors:

Detective Superintendent Tony Cook was a CID officer with Greater Manchester Police for over 31 years until his retirement in 2009. During his time as an SIO, he led a number of high profile investigations including operations into gangland violence at Moss Side, the Bolton murder of a teenage girl in 2002, and the Denton strangling case. He was a trained assessor for promotion and a qualified Authorising Officer under RIPA. Tony received 14 commendations and a first-class BSc Honours degree in social sciences and a Diploma in Social Policy & Criminology from the Open University.

Andy Tattersall, formerly Detective Superintendent
in Greater Manchester Police on the Force Major Incident Team, retired in 2007 after 33 years service and became the first ever Support Staff SIO in charge of a new Homicide Support Unit. With over 29 years in CID at all ranks Andy received the Homicide Working Group National Award for his Outstanding Achievement in the Field of Homicide in November 2006.

To see more details about the Senior Investigating Officers' Handbook, or to purchase a copy, click here.

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