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Chapter 30: Digital Guidance

Reasonable lines of enquiry

30.1. The principles of disclosure apply to computer-based electronic evidence in the same way as any other material obtained in the course of an investigation. It is a matter for the investigator to decide which material on the computer it is reasonable to enquire into, and in what manner (see paragraph 3.5 of the Code of Practice).

30.2. It is important that a close working relationship is encouraged and maintained between investigators, disclosure officers, computer forensic experts, and prosecutors.

Extent of inspection of digital material

30.3. This type of material is likely to be extensive: for example 27 gigabytes of data, if printed would create a stack of A4 paper 920 metres high. In dealing with digital material paragraph 27 of the Attorney General's Guidelines should be followed:

"Generally [this will mean that such] material must be examined in detail by the disclosure officer or the deputy, but exceptionally the extent and manner of inspecting, viewing or listening will depend on the nature of material and its form. For example, it might be reasonable to examine digital material by using software search tools, or to establish the contents of large volumes of material by dip sampling. If such material is not examined in detail, it must nonetheless be described on the disclosure schedules accurately and as clearly as possible. The extent and manner of its examination must also be described together with justification for such action."

30.4. It is the responsibility of the officer in charge of the investigation to ensure that the disclosure officer's duty to inspect, view or listen to all relevant material in the investigation is properly discharged. It is essential that the officer in charge of the investigation appoints a disclosure officer who has the skills to liaise with any computer forensic experts.

30.5. It is difficult to give firm guidance on the processes and systems deployed because they will vary according to the scale and nature of the investigation. The technology used is also subject to rapid changes and improvements. An early meeting between the investigator, disclosure officer and the prosecutor should be held to cover the processes and systems deployed. The use of keyword searches and digital evidence recovery officers is outlined in Annex H.

30.6. Where the item of media contains no evidence on which the prosecution intends to rely or relevant unused material, the item should be returned if practicable. There is no obligation on the prosecution to retain irrelevant unused material.

30.7. Where the disclosure officer cannot inspect, view or listen to all the material the duty to inspect extends to what is reasonable and proportionate in the circumstances of the case.

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Copying and inspecting disclosable material

30.8. When dealing with large quantities of digital product satisfying the disclosure test, care must be taken not to inadvertently disclose confidential or sensitive material to the defence.

30.9. Where the disclosure officer or investigator have concerns about differential disclosure of confidential information between co-accused, they should bring these concerns to the attention of the prosecutor. The prosecutor should seek agreement with the defence, and where appropriate the court, as to how disclosure may be made.

30.10. It may be appropriate to ask owners of data if any breach of confidentiality will occur if the data is disclosed to any accused.

30.11. Where the disclosure officer decides to allow inspection of disclosable material, adequate facilities should be made available where the defence can carry out their examination.

30.12. It should be stressed that the defence and their forensic expert should not be allowed direct unsupervised access to an original unused exhibit. There may be occasions when it is appropriate for the disclosure officer to allow a defence forensic expert supervised access in order to facilitate the disclosure process, particularly when the defence statement indicates that such an examination is appropriate. The investigator should agree this with the prosecutor in advance.

30.13. In multiple accused cases, the prosecution team should seek to agree an acceptable lead expert to act on behalf of all accused.

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