The Collector should be familiar with any possible risk posed to the integrity of the data by any equipment or software used and its form of use (hereinafter ‘tools and techniques’) throughout the collection effort. Various tools and techniques may have impairing effects, including by altering or degrading the audio data, stripping its metadata, or generating inaccurate metadata. From an evidentiary standpoint, these outcomes could undermine the data’s authenticity and reliability.
The tools and the techniques used throughout the collection effort should be validated to ensure they will not impact the data’s integrity. The validation of new tools and techniques should take place prior to their use on collected audio data, and should be done on known data sets so that any inconsistencies can be identified. Any possible or known impairment or risk of impairment to the integrity of the data must be documented, along with its possible or known cause and any steps taken to cure the problem.1
An error in the collection tool’s settings can result in inaccuracies in the metadata that is generated by a particular device (the ‘embedded metadata’). For example, a voice recording made with a device that is configured to the wrong time zone may display the incorrect time in the recording’s embedded metadata. The incorrect time of recording embedded in the data could jeopardise the recording’s reliability in a criminal proceeding by, for example, casting doubt on when an alleged event occurred. To ensure consistency, the Collector should take steps to ensure the equipment and tools are calibrated to generate accurate embedded metadata. The specifications to which the equipment and tools are calibrated should also be duly documented as part of the audit trail and included as a form of associated metadata (see BP 17).
External factors may also impair the accuracy of embedded metadata. For example, many devices, such as cell phones, will embed geolocation in metadata. Yet, the accuracy of a phone’s metadata could depend on the phone’s access to cell service, or be vulnerable to disruptions of GPS technology (‘jamming’) that are commonplace in conflict zones. If a voice memo is recorded with a cell phone while the device has poor or disrupted GPS connection, the geolocation data attached to the voice memo could be missing or inaccurate—for example, by portraying a different location.
The Collector should consider regularly auditing the quality of the audio data and the accuracy of the embedded metadata.
Tech Specs & Resources
For a list of points and questions to consider when deciding on new tools, see e.g., OHCHR, Berkeley Protocol, Annex V ‘Considerations for validating new tools’.
For transferable guidance on tool and technique validation, see e.g., SWGDE’s Model Standard Operation Procedures for Computer Forensics (2012), page 6.
For guidance on leveraging the consistency of the specifications to which collection tools are calibrated as a corroborative feature of the embedded metadata, see e.g., ProofMode, Three Layer Problem: Integrity, Consistency, Synchrony.
Certain smartphone applications offer a ‘controlled capture’ function, meaning the information is captured with comprehensive metadata and stored in a manner that secures its chain of custody. Examples include the EyeWitness to Atrocities app and the Guardian Project’s ProofMode app. These apps do not offer a capture option that is specific to audio, however their video functions may be used to record audio.
Note: There are no known and publicly available controlled capture applications specific to audio data at the time of this Protocol’s completion, although such tools are known to be in development.
Legal Framework
See section 5.2. and section 5.3. on the importance of accurately documenting the date and circumstances of the collection of information when establishing the relevance and probative value of evidence.
See also Prosecutor v Bemba (ICC), Public Redacted Version of ‘Decision on the Prosecution’s Application for Admission of Materials into Evidence Pursuant to Article 64(9) of the Rome Statute’ of 6 September 2012, para. 84, wherein the Trial Chamber refers to the role of ‘date, circumstances and context in which the recording was created’ in establishing relevance and probative value.
Applicable Ethical Principles Accountability; Accuracy, Impartiality, & Objectivity.
Footnotes
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This is an extension of the requirement stated in BP 3 that Collector ‘personnel must at all times strive to document the collection effort in a manner that is as consistent, clear, and transparent as possible’: Prosecutor v Ongwen (ICC), Trial Judgment, para. 658; Prosecutor v Ongwen (ICC), Confirmation of Charges, para. 51; Prosecutor v Ongwen (ICC), Transcript, para. 44, lines 8-24; Prosecutor v Tolimir (ICTY), Judgment, para. 64, referring to Prosecutor v Tolimir (ICTY), Transcript, page 5033; Prosecutor v Blagojević and Jokić (ICTY), Decision on Admission of Intercept Materials, para. 21; Prosecutor v Katanga and Chui (ICC), Decision on Bar Table Motion, para 30. See the discussion in sections 5.2. and 5.3. of the Legal Framework. ↩