Thursday 10 October 2013

Madeleine McCann - Phone Records, Forensics & big data

Madeleine McCann, aged 3, disappeared from a holiday villa in the Portuguese resort of Praia da Luz on the evening of the 3rd May 3 2007. Despite one of the largest publicity campaigns and worldwide searches in history, she remains missing. Her parents, Gerry and Kate, have led a campaign to find their daughter, refusing to give up hope.

In 2011, Prime Minister David Cameron, ordered a fresh review of the original Portuguese police investigation and drafted in thirty Scotland Yard detectives to help sift through the vast volumes of information and witness statements. So far, just over half of the forty thousand pieces of information collected by the Portuguese authorities have been assessed, but progress is being advised as being positive.

Now there have been similar stories in the press over the years, but what makes this one so interesting is its renewed focus on digital forensics. Investigators believe telecommunication records could hold the key to solving the case and are focussing their search on thousands of mobile phones, thought to belong to people who were in Praia da Luz in the days leading up to, during, and after Madeleine's disappearance.

Detective Chief Inspector Andy Redwood, who's leading the inquiry, says officers are trawling through a 'substantial amount of data' and have so far identified 41 persons of interest. With around three thousand people living in the Algarve holiday resort, and thousands more visiting during the holiday season, this task is neither straightforward nor complete. This exemplifies ‘big data’ and the complexities of effectively data mining to find those crucial (digital) needles in the haystack.

In fact, DCI Redwood admits his team have been unable to attribute (link to a named individual) a 'large number' of mobile numbers, largely due to the fact that six years have now passed and a considerable number were bought on a 'pay-as-you-go' basis. This reflects an increasingly common practice for individuals travelling overseas to buy a cheap PAYG SIM from a local vending machine or shop, so as to avoid roaming charges and benefit from local call/data rates.

Call Data Records, sometimes referred to as ‘billing records’, will show the timing, volume and patterns of communications activity. The numbers dialled, the duration of voice calls, numbers that have been sent text messages, and instances of access to voicemail. The content of the spoken conversations or the typed details of a specific text message, will not be available, but the broader picture of activity can still be important.

Then there's the issue of tracking down the thousands of holidaymakers that were in the Algarve resort where Madeleine McCann was staying when she vanished. Scotland Yard have already made contact with thirty one police forces across the world to help them piece together the records and make contact with the owners of foreign mobiles.

A powerful investigative technique is being applied to mobiles of interest – Cell Site Analysis. The intention is to identify mobile devices that engaged telephone masts in and around the Algarve holiday resort on the days surrounding the incident. The users of these devices can then be tracked down and interviewed – one of the owners may prove to have seen/heard something that could take the investigation in a whole new direction.

Crimewatch will be airing a special on the Madeline McCann investigation this evening – with exclusive interviews, fresh evidence, and a scene reconstruction.

We would welcome the thoughts of other practitioners and experts in this field on the forensic evidence in this case and other avenues of investigation that could be explored.



** Note: Afentis Forensics have had an involvement in this investigation and whilst open debate and discussion is encouraged, please could comments keep in mind the sensitivity and emotive nature of the matter.

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