Scene strategy

Managing scenes

The way in which a crime scene is managed affects the quality, quantity and integrity of the material gathered. It is, therefore, essential that investigators identify and prioritise crime scenes, as they may contain material vital to the successful outcome of the investigation.

Once investigators have identified a scene or multiple scenes, they should make an initial assessment of its potential to provide material. The assessment and subsequent formulation of a scene strategy (which should include necessary resource allocation) should have due regard to forensic strategy considerations. Undue delay or failure to consider forensic issues at this stage may lead to valuable material being contaminated, overlooked or lost.

Investigators should be mindful of the impact that securing and managing a scene can have on a community. They should consider community engagement strategies.

For further information see:

• APP on engagement and communication
• NPCC (2021) Major Crime Investigation Manual (MCIM)

Crime scene investigators (CSIs) and managers

The extent to which investigators are responsible for managing a crime scene and developing crime scene strategies is influenced by the complexity or seriousness of the investigation and local force policy.

When gathering material, investigators should liaise with CSIs and managers to ensure that they use the most appropriate method for examining the scene.

Identifying scenes

The crime scene can present itself in a number of ways and may not be immediately obvious to the investigator or initial attending officer. There may also be multiple crime scenes which relate to the offence.

Scenes could include:

• the victim
• witnesses
• routes to and from the scene
• the suspect
• weapons (including live and spent ammunition)
• the suspect’s home address or other premises associated with the suspect or the commission of the offence
• vehicles (including boats and caravans)
• deposition or dump sites (including victim, clothing, weapons or stolen property)

The scene of the offence is usually relatively easy to identify, and this should be considered a fast-track action (see Initial investigation). Multiple scenes may need to be prioritised. Victims or witnesses may be able to tell investigators precisely where and how the offence was committed. This helps investigators to secure, search and preserve the scene at the earliest opportunity, and to recover the best possible material in a manner which preserves its integrity.

For further information see Preserving the scene.

Securing the scene

The purpose of securing a scene is to maintain the integrity and provenance of any material which may be recovered from it. This simple and important action reduces the opportunities for the material to become contaminated or inadvertently cross-contaminated.

There are a number of methods the investigator can use to secure and manage crime scenes. They include:

• using tape to prevent access to or from the scene
• deploying officers to guard the scene (care should be taken to ensure that officers attend only one individual scene in order to prevent cross-contamination)
• using vehicles as barriers to prevent entry
• setting up roadblocks to protect wider scenes
• erecting temporary fencing
• using road diversions
• ensuring that persons entering the scene are wearing suitable protective clothing to prevent contamination of the scene, and to ensure that they are protected from any hazards present
• using a scene log to manage and record all activities within the crime scene

Requests for third party access to a scene to attend a victim

Immediately after an incident involving death or serious injury, a third party (not a member of the emergency services) may make a request to access the scene to attend the victim. This may include, for example, a priest, of the victim’s faith or religion asking to administer Last Rites or other religious needs, or a family member wanting to comfort a loved one. While these requests are likely to be rare, they can be extremely important for the victim and their family (see Major Crime Investigation Manual, page 115 for a definition of the term ‘family’).

Such requests are likely to be relevant where the victim is known, by the third party, to still be at the scene. This would not include planned crime scene visits for family members supported by a family liaison officer. A priest, for example, who might make such a request, will be familiar with ministry to the dying.

The decision to admit third party access to a scene is an operational decision and should be made by the senior investigating officer (SIO), or an incident commander where an SIO has yet to be appointed. Where an SIO or incident commander is not available requests should be referred to a supervisor for support.

When considering such requests, decision makers should apply the national decision model (NDM), and the principles set out in the College of Policing Code of Ethics. They should also consider articles 2 and 9 of the European Convention on Human Rights (ECHR), and whether the purpose of the request can be accommodated without the third party entering the scene, for example, standing at the edge of the scene, close to the victim.

The decision maker must balance medical and investigative priorities and requirements, with empathy for the victim, their family and any religious needs.

The following should also be considered.

• The immediate priority to save life, administer first aid and move the victim to hospital for further treatment. These actions will be time critical and subject to the judgement of medical personnel.
• Health and safety in and around the crime scene, including whether personal protective equipment would be required.
• The need to secure and preserve the crime scene and the material within it (consult with the crime scene manager).
• The complexity of the incident, the potential risk to the integrity of the investigation and the suspects right to a fair trial (Article 6 of the ECHR).
• The rights and needs (including religious rights and needs) of the victim and their family (notwithstanding the status of family members in the investigation).
• The potential effect of granting, or not granting, access to a family member.
• The status of the family member(s) in the context of the wider incident, for example whether a family member may also be a suspect.

Where the victim has suffered significant trauma, the family should be briefed so they can make an informed decision about seeing their loved one.

Every incident will be unique, and all decision making should be recorded with supporting rationale.

Article 2 of the ECHR provides a right to life. Public authorities should consider the right to life when making decisions that might put an individual in danger or that affect life expectancy. The state is also required to investigate suspicious deaths and deaths in custody. See also the Major Crime Investigation Manual.

Article 8 of the ECHR provides the right to respect for private and family life. An individual has the right to enjoy family relationships without interference by a public authority (this could be interpreted to include having access to a loved one where they are injured or dying). There are situation where public authorities can interfere with this right. This includes where it is necessary to protect national security, public safety or to prevent crime or disorder.

Article 9 of the ECHR provides the right to freedom of thought, conscience and religion; however, the right to manifest one’s religion (which could be interpreted to include the administration of Last Rites to the dying) is subject to limitations as are prescribed by law and are necessary in a democratic society in the interests of public safety, for the protection of public order, health or morals, or for the protection of the rights and freedoms of others.

Cross-contamination

The techniques of crime scene management are based on Locard’s principle of exchange. Anyone who enters the scene both takes something of the scene with them and leaves something of themselves behind. This means that every contact leaves a trace, however miniscule. This could be:

• fingerprints
• DNA
• fibres
• footwear marks

Particular care should be taken regarding DNA anti-contamination procedures due to the ease with which DNA may be transferred (coughing, sneezing etc.). Force DNA anti-contamination protocols must be followed.

These traces provide valuable material that can link a suspect to the crime. The techniques for recovering this material are highly specialised and CSIs have the necessary training and equipment to carry them out.

Equally, the movement of police officers or staff between scenes may cross-contaminate the available material, and confuse or mislead the investigation. If in doubt, officers should seek advice from CSIs or crime scene managers.

For further information see Crime scene DNA anti-contamination guidance.

Preserving the scene

The investigator should seek advice from CSIs or managers to determine the appropriate level and method of protection required. This may include covering or lighting the scene and identifying and protecting access routes to or from the scene.

Risks to the scene which may need to be managed include:

• damage being caused by exposure to the elements
• animal disturbance
• disturbance by material being moved from its original position (for example, during initial attendance of paramedics)
• microbiological activity causing decay to material
• disturbance by items being taken into it
• disturbance by material being removed from it
• cross-contamination by transference between scenes

If scenes are not properly managed, this can distort initial findings and prolong subsequent efforts to identify offenders.

Managing the media

Where the media attend the location of a crime, access to the scene should be carefully managed, both to protect the scene and for health and safety reasons. The investigating officer must decide when access to the scene should be allowed, but in some circumstances they may wish to consult their press office for advice and help. Media access should be under direct police supervision and media representatives should wear high-visibility jackets while at the scene. The media should be encouraged to obtain the information they want as quickly as possible, and their equipment, for example, high powered lighting, must not be allowed to endanger others.

Searching and examining the scene

Search

It may be necessary to search the scene before examination takes place. Protection of life always takes primacy over the preservation and recovery of forensic material.

For further information see Search strategy.

Examination

A thorough examination of the scene is essential. As there is usually only one chance to do this, scene examination should not be made in haste unless a delay would result in the decomposition of evidence. Relevant experts should be consulted, where necessary, before commencing the examination.

Investigators should be clear about what they require from the examination of a scene. This usually includes identifying:

• material taken to or from the scene by the offender or the victim
• access and egress routes to and from the scene
• any passive data generators which may be of use to the investigation

In major or complex scenes where several crime scene investigators are required, a crime scene manager should play an active role in managing all aspects of the scene examination.

As soon as examination is complete, the investigator should consider releasing the scene.

Releasing the scene

Investigators should not release a scene until they are satisfied that all expert advice has been considered and that a police search adviser (PolSA) team has conducted a full and final search, if appropriate.

Once areas which have been covered by crime scene tents and stepping plates have been searched, the scene can be cleaned and released. In some cases, this may need to be conducted in liaison with the environmental health department or the local health authority, for example, where chemicals or biological substances may have been found.