Conducting effective investigations

These guidelines provide clear evidence-based practice guidance on how best to ensure that investigations are conducted effectively, regardless of offence type or complexity. They are not intended to be a full description of the investigative process and should be read in conjunction with authorised professional practice (APP) on Investigation. 

An effective investigation involves:

• understanding your role in an investigation and your contribution to the process
• being open-minded, professionally curious, and identifying and following all lines of enquiry
• being proportionate, understanding, and being aware of biases
• employing good interpersonal skills

These guidelines specify and detail the actions and behaviours required to support effective investigations.

These guidelines also set out the actions that chief constables and supervisors need to take to support and enable their staff to conduct effective investigations.

These guidelines are for all investigators – including those who do not carry an investigative caseload, but who may have an impact on or may influence the effectiveness of an investigation. For example, supervisors and managers, call handlers and police community support officers (PCSOs).

The guidelines consist of:

• three practical guidelines for investigators
• one guideline for supervisors, which sets out the support required to enable staff to conduct effective investigations
• one guideline for chief constables, which sets out the organisational focus, structures and processes required to support and enable effective investigations

The type and strength of the evidence underpinning each guideline is shown as follows.

• Overall strength of the empirical evidence (good, moderate or limited).
• Practitioner evidence available.

The supporting information that follows each guideline includes a brief summary of the evidence and what the guideline might mean in practice, drawing on existing guidance and practice as appropriate.