Defending Criminal InvestigationsThe Ultimate Guide

A criminal investigation is not a single event. It is a sequence of decisions made on changing information. This guide follows that sequence: how an allegation becomes an investigative theory; how immediate decisions create evidence and risk; how state powers are exercised; how a defence case is built; and how the eventual outcome is influenced, reviewed and secured.

The chapters can be read in order or used at the point that matches the reader’s position. The first three establish the analytical method. Chapters Four to Ten address the first response, voluntary attendance, arrest, custody, interview, evidence-gathering powers and release. Chapters Eleven to Fifteen address defence development, privilege and ethical control, representations, continuing investigations and closure.

Four distinctions govern the guide

• A complaint or report is a source of information, not proof.
• Evidence and the interpretation placed upon it are not the same thing.
• A legal power, a request and consent are different routes with different consequences.
• Urgent action, purposeful engagement and strategic restraint each require a reason and a review point.

Language

‘Client’ is used for the person or organisation receiving advice. ‘Investigator’ includes police and, where the context permits, other investigative bodies. Powers and procedures differ between regimes; police procedure is not silently applied to regulators or specialist agencies. ‘NFA’ means no further action in relation to the identified decision, not an acquittal or universal deletion of records.