Forensic Science: Interpreting The Evidence 8 Years On

In June 2010 we published our first website article called “Forensic Science: Interpreting the Evidence”.  Back then, Cell Site Analysis was in its infancy, and the drastic cuts to the money spent on forensic science had not begun.  The article looked at how interpretation done by the right person can help to elucidate critical findings for the Court.

Here we are, 8 years later, and it is interesting to see if the same still applies, or have things have changed?

In many ways the issues are the same.  We still need to look at forensic evidence not only in terms of ‘what it is’ but the more subjective question of ‘what does it mean?’.  It is the process of reconstructing an event in the past by putting evidence into context and looking at it from various perspectives.

Yet the last 8 years of austerity have changed the foundation on which this kind of analysis lies.  Less is being analysed by the forensic laboratories which raises the profile, not just of what evidence we have, but what hasn’t been done and why?  Are critical evidential items being held back from analysis to save costs?  Are we losing key areas of expertise through attrition?  Is the interpretation of forensic science findings being done by non-experts?

Cell site analysis, for example, is now commonplace and has evolved in complexity. It no longer consists of looking at the masts used when making simple texts and calls. Cell site analysis now involves mobile data which can generate thousands of location entries, and, more recently, Device Data Records which are short communications between a phone and the network used for system updates that the customer never sees or knows, yet are generated, potentially in their thousands, per case.

All of the data has to be formatted, sorted and then interpreted.  What was once a relatively simple task can now be drowning in hundreds of thousands of entries.   Understanding the relevance of these in the context of a case has never before been so voluminous, and the time taken to do this kind of work has increased significantly.  At the same time pressures have moved Court deadlines toward speedier justice.  The result is the frequent late serving of cell site evidence and as a result, reduced time for the defence to fully absorb it.  Getting copies of raw data to work from can take weeks, despite the fact it had been received by the police months earlier.

The same is true for the examinations of computers, tablets and mobile phones.  The modern mobile can hold as much data as a powerful PC, and the ability to be able to view, sort and capture relevant material is becoming more complex and time-consuming.  Examinations are often focussed on looking for key phrases or words in a case, but the problem is that they can be extracted out of context.  A WhatsApp message stating, “Im looking for some water sports gear” may seem relevant in a drugs case, but if the next message is, “I need a mask and snorkel as the kids are off swimming” then it’s apparently not.  This may seem exaggerated, but we have seen a case where this is what happened.

And this is where, after 8 years, we are seeing a new kind of problem.  In years gone by, if you had a question about what the forensic results mean, you asked the scientist.  In the current climate, we are seeing results being gauged by those who lack the wider context expertise.  One medium for this is the SFR1 report, produced in order to try and simplify issues and reduce costs in non-contentious cases.  Yet these overly simple, forensic preliminaries end up being dropped into contentious cases without any finesse or afterthought, despite CPS guidance that is not supposed to be done.  The relevance of the findings is often not being assessed at all as to what the results really mean.

The issue is much like taking a modern car to the dealership to diagnose a fault, but asking them to give you the fault code and not figure out what the code means.  You can see how ‘self-diagnosis’ may end up leading you up a very different path compared to a mechanic who is an expert in the interpretation of the codes.

We have seen problems with ‘self-diagnosis’ across the forensic disciplines, including:

• Fingerprints:  No interpretation was done of how the fingerprint got to where it was found.  On review, our expert proved it could not have been placed at the time of the incident.
• Cell Site Analysis reports being prepared where the author states that they are not an expert yet the report contains expert opinion critical to the Crown’s case.  In one case, the cell site timing was out by 4 hours.  In another, the suspect was very likely 3 miles away, in the place that he said he was.
• DNA SFR1 reports stating a match was made but not mentioning the other (and sometimes stronger) non-matching profiles or different profiles found on other samples from the same item.
• Cannabis cultivation yield estimates being written by non-experts by simply multiplying the numbers of plants by an average, without consideration of plant health, plant size, plant maturity, number of lights, physical capacity, and number of unrooted cuttings.
• Failure to disclose exculpatory material, sometimes discovered by persistence or even accidentally during an examination by the defence.   We have seen examples of this in alleged sexual assault cases where images and conversations supporting the defendant’s account were present and easy to find, yet not included in the Crown’s case.

What has changed in 8 years is not the need to interpret – that still remains.  We has changed is the additional need to consider what should have been done in order to properly evaluate a case.