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13.3.3 COMMON CONSIDERATIONS
Although there will be variation in the technical requirements needed to gather, use and store the data from passive data generators, there are a number of common factors which SIOs should consider when setting objectives.
Speed of access – in many cases data is only stored for a limited time, so if it is not identified and secured, it may be lost to the enquiry.
Ownership – all passive data is owned by someone. While this is no bar to it being used, there is likely to be a cost and some inconvenience to data owners. SIOs will often, therefore, be relying on the goodwill of data owners to access records to look for anything that may be of value.
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Legal constraints – there may be legal constraints on how the police can access and use data. SIOs should be certain that they have the appropriate level of legal advice to ensure that they are accessing and using passive data in legally valid ways.
Access to some of the material which these systems generate is governed by legislation such as the Regulation of Investigatory Powers Act 2000 (RIPA) or PACE.
Investigators should also take account of the provisions of the Human Rights Act 1998, notably respect for private and family life. Additionally, investigators must be aware of the agreed protocols, eg, the Communication Service Providers (CSPs) have agreed protocols which permit investigators to preserve and access call data records.
To ensure consistency and conformity with these protocols, identified individuals have been trained and accredited to act as single points of contact (SPoC) for each force. Investigators requiring information and advice about obtaining material from CSPs are advised to make early contact with the SPoC.
Technical Issues – there is a high degree of variation in the type of storage system used by passive data gatherers. In addition to obvious differences, such as those between the use of tapes to store CCTV images and computers to store telephone billing data, there may be large differences in the technical specification of systems used for storing a particular type of data. Investigators will be familiar with the wide range of systems used to store CCTV images and the problems this can pose for viewing, storage and use. It is not possible in this manual to list all the technical issues that SIOs may face when dealing with passive data generators. Moreover, the speed of technical innovation means that such information can quickly become outdated. SIOs should ensure that they have access to the most up-to-date technical advice and support that is available in relation to the passive data gathering systems they are seeking to use. Sources of advice are:
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Scientific support units;•
National ANPR data centre and force ANPR data managers.Integrity – maintaining the evidential integrity of material obtained from passive data generators is an important consideration for SIOs. When they have sufficient understanding of the technical issues involved, they should implement a regime that ensures that courts can be satisfied that the material has been handled in such a way that its evidential value has not been impaired.
Volume – passive data generators tend to gather large volumes of data. Even where SIOs are able to set tight parameters, it is likely that those tasked with searching for specific material will have to manage a high volume of data in order to locate it. In setting objectives, SIOs should consult technical experts to identify the various methods by which data owners analyse it as these may be adequate for the needs of the investigation. If this is so, they are likely to be quicker than other alternatives. In other cases, SIOs should task the analytical manager with developing a suitable method of analysis.
13.4 IMPLEMENTING THE STRATEGY
SIOs should ensure that the managers who are tasked with overseeing the implementation of the passive data generator strategy have the ongoing support of the appropriate technical specialist. This may be most easily arranged through the specialists consulted at the time the strategy was developed.
Managers should also be conversant with the legislation governing the police use of the data, and any relevant national or force policy. Where it is proposed to make extensive use of particular types of passive data, or it is thought likely that it will be central to a prosecution, SIOs should consider obtaining the services of a full-time legal and procedural adviser. This is particularly the case with telecoms data and financial information where, in addition to specific legislation covering its use by the police, there is also a national policy governing the way in which the police liaise with private providers.
In the case of CCTV or other images, SIOs should ensure that they use staff who are experienced in viewing this kind of material. An analyst may be required to fully exploit ANPR material. This is particularly important when images from different cameras are being viewed. Issues which often prove problematic are the synchronisation of the timings of different cameras and the criterion used to confirm the identification of individuals. The latter can be particularly difficult where the quality of the image is low. The use of experienced staff will ensure that such issues have a minimum impact on the investigation.
The material obtained from passive data generators can provide a powerful way of corroborating and challenging material supplied by witnesses and suspects during investigative interviews.
Investigative interviews can also identify passive data generators that may provide relevant material. Interview plans should, therefore, include questions designed to obtain information about the suspect’s movements, vehicles, financial activity, computer use and material that may, in the circumstances, identify passive data generators.
SIOs should ensure that interviewers preparing suspect interview plans have full access to the material obtained from passive data generators. This is because it is likely that interviewers will wish to elicit a suspect’s account of a particular activity that can be corroborated by such data, before revealing its existence. Care should be taken not to inadvertently reveal its existence to suspects during arrest or custody procedures. For example, the existence of CCTV images, ANPR material, telephone billing data or financial information linking the suspect to the offence, should not be used as a justification for detention if it could compromise the interview strategy.
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Given the likely high cost of implementing the passive data generator strategy, both in terms of the costs imposed by data owners and of enquiry staff time, it is essential that the objectives and the parameters of searches are kept under constant review to ensure that they are as precise as possible. This is particularly important in the case of telecoms data where the desire to explore the links between telephones can lead to spiralling requests for billing data, as each new set of data reveals more telephone numbers that could be explored. Maintaining the focus on the objectives of the strategy, adjusted where necessary in the light of new material, will ensure that cost spent acquiring data will be kept to a minimum and that the investigators’ time is not wasted.
13.5 FURTHER READING
Further advice and guidance for investigators on the retrieval of intelligence that may be held within computers and portable IT systems can be obtained from within force computer and IT units.
Information regarding access to banking records can be obtained from force economic crime units.
Additional information is available from the ACPO (2003) Good Practice Guide for Computer-Based Electronic Evidence.
For further guidance see ACPO (2005) Core Investigative Doctrine, Section 6.7 Passive Data Generating Strategy.
At the time of publication, an investigator’s guide to the uses of ANPR material is being developed. This will cover a range of issues including analytic options, reactive and proactive strategies, presentation of evidence, and RIPA.