This week we look at the way evidence should be interpreteded and the importance of never accepting material or evidence at face value

In this series, we preview sections of Blackstone's third edition of the Senior Investigating Officers' Handbook. This book provides invaluable insight about the essential skills and responsibilities that a senior investigating officer needs to manage serious crime investigations, from the initial response through to crime scene examination and investigative strategies. PoliceOracle.com readers can enjoy a 20 per cent discount on the book with our special offer code at the end of the article.

The ‘ABC’ Rule

Decision making also relies upon good information which must be carefully scrutinised, reviewed and assessed. It involves remaining sceptical and testing the accuracy, reliability and relevance of material relied upon. This rule is known as the ‘ABC’ principle:

A—Assume nothing
B—Believe nothing
C—Challenge (& check) everything

Nothing should be taken for granted nor accepted at ‘face value’. It is a mistake to assume things are what they seem. SIOs must try to seek corroboration, recheck, review and confirm facts, information and material. Applying scepticism is the best approach before placing too much reliance on information. Good SIOs are confident and wise enough to remain sceptical and challenge or check everything by good probing

Problem solving

Decision making involves an element of problem solving. Detective work requires a sequential and logical approach and there are some useful techniques aimed at simplifying the process. 

The aim is to incorporate a methodical collection and analysis of information and alternative solutions into a process that will help generate well-informed decisions. Good problem-solving skills are an important part of decision making and will produce different options, leading to a more informed, rational choice and decision. 

There are different varieties of problem-solving models, though most contain a similar structure. One recommended contains a simple step by step process and involves choosing a course of action or decision only after collecting sufficient information, then analysing the pros and cons of alternative solutions before making a choice.

The ‘investigative mindset’ rule applies when considering alternative solutions and options for making key decisions. The more alternatives considered, the greater the chance of not missing the best option or solution. The decision may be to choose various options for different tactical stages and timescales of an investigation, eg in the short, medium or long term. Alternative options can also be graded as part of a contingency, eg plan A or plan B.

One method of analysing the pros and cons or advantages and disadvantages of options is to examine their strengths, weaknesses, opportunities and threats (SWOT analysis). For example, looking at what threats there are (such as time, resources and cost implications) against what opportunities the option can provide.

‘Do nothing’, ‘defer’ or ‘monitor’ options

Sometimes a decision has to consider whether any action is necessary. It may be, for example, that cost outweighs gain. Therefore there may be an option to ‘do nothing’ (ie take no further action), ‘defer’ (put off until later) or ‘monitor’ (eg wait and see). In an arrest decision example, it may be that a suspect is detained in prison or critically ill in hospital. This may provide an option to ‘defer’ an arrest until such time it becomes feasible—a decision that can be monitored and remain under review.

About the authors

Former Detective Superintendent Tony Cook was a career detective and senior investigating officer with Greater Manchester Police until he retired in 2009. He is currently a PIP Level 3 and 4 Regional SIO Advisor with the National Crime Agency.

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.

Blackstone's Senior Investigating Officers' Handbook is designed specifically to meet the quick-reference needs of any officer conducting a serious investigation. The only portable step-by-step guide to the processes and actions involved in the role of a Senior Investigating Officer (SIO), it explains all the relevant procedures and instructions integral to the position in a clear and accessible style.