Introduction

When you are investigating a suspected criminal offence you will need to obtain evidence. "Evidence" is any material relevant to proving or disproving the commission of an offence(s). It will commonly consist of:

• witness statements;
• transcripts of interviews under caution;
• documents;
• physical evidence (also known as "real" evidence);

In every criminal trial under Scots law before a person can be convicted of an offence there must be corroborated evidence to prove beyond a reasonable doubt two essential facts:

• that an offence was committed, and
• that the accused is the person responsible for committing the offence.

Corroboration has nothing to do with the admissibility of evidence, as is sometimes thought. The legal doctrine of corroboration requires every essential fact to be proved by evidence from at least two sources. Evidence can be direct (eg eye-witness accounts) or indirect (or circumstantial) - both are equally valid. Even if there are no eye-witnesses there may still be sufficient evidence to prove an offence, for example, where one witness sees an accused with an axe in his hand standing beside a freshly felled tree and another witness hears the accused admit to cutting it down, the evidence of the second witness would corroborate that of the first witness.

The Police and Criminal Evidence Act 1984 (PACE) does not apply to Scotland. The use of tape recording equipment by the HSE when interviewing suspects is not practised in Scotland. However, for certain high profile investigations, particularly if carried out jointly with the police this policy may need to be reviewed in consultation with the Fiscal on a case by case basis.

The order in which you collect evidence is important. As a general rule you should interview workers before supervisors and members of management. However, when workers themselves are potential suspects they should also be amongst the last to be interviewed. If you need specialist advice or support for your investigation you should obtain it at an early stage. You need to consider the question of fault, ie who is legally responsible for the incident under investigation and to what extent. This will involve consideration of the law, codes of practice and guidance, previous contacts with duty holders, manuals, trade journals, and the like. Only when your investigation is nearly complete should you seek the views of, and mitigation from, a director or other senior officer. You should not forget that at any stage in your investigation you may need to go back to earlier witnesses and put to them documents or comments that you have received subsequently.

If a work related death is being investigated then you should implement the requirements of the Scottish Work Related Deaths Protocol in relation to liaison with the police and Procurator Fiscal, and the conduct of the investigation.