The impact that Cell Site Analysis can have on an investigation

The article “Cell Site Uncovered” featured in a recent issue of the Investigator Magazine and has attracted interest from Police forces as far afield as New Zealand

Within every group, community or organisation there are sceptics, this is a fact and occasionally they have been proven to be wiser than the masses.  However, when we consider the benefits of Cell Site Analysis as part of a criminal investigation we must acknowledge that this technique is of great value.

Since the turn of this century, the sceptics have announced that the criminals will become wise to the use of phone analysis, they will ‘drop’ their phones or they will use ‘dirty’ phones that cannot be attributed to them….the criminals will become technically aware and avoid capture through the avoidance of generating telecommunication data.  Readers with a sceptical view need read no further as all serious crime and criminal investigations continue to rely on evidence from call data records and with the exponential rise in the use of smartphones and data connections, more so today than ever before.

Should it therefore be recognised that Cell Site Analysis is the modern ‘DNA’ of evidence?  In truth, no.  Of course we appreciate that mobile phone call data records are comparatively a new addition to the ‘tool box’ of the detective but we need to fully understand how call data records may influence or enhance an investigation, it is not a case of replacing traditional investigative methods with Cell Site Analysis.

It is often the case that suspects are identified prior to the phone data becoming available, but not in all cases.  Occasionally, a phone of importance may be identified but not attributed to any known person.  Regardless, the phone data will show aspects of contact between significant persons and reveal cell locations that handled calls during periods of interest.  So how does Cell Site Analysis progress the evidence or intelligence?

The location of masts and the direction and coverage of cell identities may assist investigators in identifying potential events of interest, but these will rely on other information being known or thus  to be established, anything less is pure guess work or an inference.  Frequently data is compared to ANPR captures or CCTV images and then the story may begin to unfold.  Witness accounts, surveillance records and suspects interviews can all be considered alongside the phone records, which provide an accurate, reliable timeline.

As you will have read, so far there has been nothing remarkable in the introduction of this relatively  ‘new evidence’ and it would be fair to say that evidentially it may be described as supportive or corroborative of circumstances already known to the investigators.  If the last comment is accurate, then many a prosecuting counsel may be delighted as the testament of witnesses can be further scrutinised as to their truth or bearing.

So when does the evidence become that of opinion and then provided by an expert?  The connection of mobile phone handsets to the Network is subject to the radio frequency coverage of antenna located on cell site masts.  The areas of coverage are influenced by many factors; topography, building clutter, mast height and positioning, etc.  There is no standard coverage area to any cell site, although this is one of the most commonly asked questions.

A suitably qualified expert would be able to use their knowledge and experience in commenting on potential or likely areas of coverage of any cell site but ultimately would need to rely on radio frequency surveys to provide robust or specific evidence.  There is much discussion as to the manner in which surveys ought to be conducted and even whether the person undertaking those surveys should be an expert or not.  I am sure that all those who hold differing opinions will continue to disagree on best methodology, however it should be understood that whatever method used should be fit for purpose, i.e. the methodology used should be relevant and proportionate in order to answer the specific issues accurately.

In the same way that no two serious criminal investigations are the same, then there is not an ‘off the shelf’ solution as to how cell site analysis should be conducted.  It is the investigators who identify the matters that require the opinion of the expert and the parameters of the analysis should be established prior to the work being carried out. It is only at this point that the expert should consider their methodology in order to achieve the appropriate production of a report, including the need to conduct surveys and how such readings should be undertaken.

It is not appropriate that the expert should direct the investigation, but it is essential that those who commission the expert’s report are aware of the options available.  The style of reporting cannot be determined without fully understanding the parameters that are significant.  If a question or a contention is identified, then the expert can provide the most relevant answer.  Too often, reports are served that ‘explain’ the call activity and general movement of phone(s), but the same reports do not actually address or answer any issue, concept, belief or account.

The best expert reports are produced when officers fully understand what Cell Site Analysis is able to achieve and there is a comprehensive awareness of the relevant points that investigators wish to be considered.  Questions or contentions that are to be addressed should be clearly identified and any subsequent report produced should be clear and jargon free. Presentation of supporting material, i.e. maps and schedules should be clear and easy to understand for the jury.

It is only after the scope of the work is understood that the expert needs to decide the best methodology in conducting surveys as these are often of great significance and may be challenged at court.  It is our belief that surveys are best conducted by the expert who is able to monitor the measurements as they are captured.  This action will at least allow that expert to identify any anomalies on site, consider additional surveys, conduct further test calls and then be able to provide an educated response to questions asked of them.  After all, the surveys are part of the expert’s investigation and will be relied upon during the presentation of evidence which must stand up to in-depth scrutiny.

Cell Site Analysis should not be provided as a ‘standard’, ‘off the shelf’ or ‘one size fits all’, product.  It is part of the investigation and like all lines of enquiry relies on instructions or actions. The interpretation of call data records is an expert opinion and therefore must be credible, reliable and relevant.

The quality of the evidence produced is therefore influenced by many factors, but there can be no doubt at all, it is only an extension to traditional detective skills.  It will often support or refute an account, it may prove or disprove an alibi and it may support or destroy a witness account.  When used appropriately Cell Site Analysis is often ‘pivotal’ in proving both complex and simple cases.

Footprint Investigations are able to offer advice on cases where Cell Site Analysis may assist.  Initial consultation is free and suitable solutions will be identified for the investigators to consider.  For further assistance please contact; Andy on 01527 467467 or