An investigation should be a rigorous search for material to bring an offender to justice. This area of APP provides guidance on the key roles and principles which are based on the collective experience of the police service and literature on the process of criminal investigation.

It applies to all levels of criminal investigation, from volume to major, and includes both reactive and proactive investigations. It supports the professionalising investigation programme (PIP) and provides an outline of the skills that investigators require at levels 1 to 3.

National support for law enforcement agencies

Call NCA Major Crime Investigative Support (MCIS) on 0345 000 5463 for strategic and tactical investigative support. For more information, please see the MCIS poster (which should be treated as official).

A full index of the content of Investigation APP is available.

Investigation APP consolidates information from a number of decommissioned documents. For a full list of titles click here.