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Ask Laura

Please post your questions for this week in the comments section. Laura will select the most liked/interesting questions and publish her response to these on this step by Wednesday of Week 6.

I hope you are all safe and well and I thank you very much for all your excellent questions and comments again this week, I hope you are enjoying the final week of the course, bringing together all of the scientific evidence we have looked at as the case has unfolded. This week, your questions were almost all about the case itself, so I’m going to focus on this in my answers. In previous weeks I have tried to answer questions that are less directly related to the case so that your knowledge and understanding of the science develops alongside the evidence being presented to you in the case, but since we are now nearing the end of the course I will try to clear up some of your issues with the Murder by the Loch. Hopefully any remaining questions you have will be cleared up in the final big reveal of the verdict on Friday…

Firstly though, a question from Ernest Atlee about drugs and databases.

In the UK, forensic service providers all have their own drug testing labs and usually the key issue is just to identify an unknown substance as being a specific controlled drug (using presumptive/confirmatory testing). However, drug profiling is also possible to determine the components present in the substance in question and to estimate the amount of each component (e.g. the drug, cutting agents, impurities). Many street samples contain cutting agents to bulk up the drug for sale, for example, a sample of heroin might also contain diamorphine, paracetamol, and caffeine, and potentially also things like mannitol (a sugar) or anti-fungals. Identifying these different components of a sample can be useful in linking different batches of drugs together, and also in linking drugs to a production site/lab.

The extent of testing done all depends on what type of case it is—if the police are only charging someone with possession of a drug then the purity would not be important and the forensic analysis would simply involve identifying the drug. However, if someone was being charged with supplying or manufacturing a drug, then the purity would be tested in order to estimate the street value of the sample seized, and this could influence a sentence or fine later on.

In terms of central coordinated databases of drugs, forensic providers maintain their own databases and regularly make this information available to police, documenting the different types and quantities of drugs found in a given time period. There are also some projects collecting data to monitor seizures of different types of drugs when recovered in relatively large quantities, and these can be used for intelligence purposes. In the UK, therefore, we do not have one single national database, but agencies such as the National Crime Agency and the Advisory Council on the Misuse of Drugs oversee trends and data relating to all aspects of drugs.

Now on to the case…..

In previous weeks there have been several questions about whether any fingermarks or DNA could be recovered from the gun after it had been in water, and generally whether any other useful evidence was found on the gun. The answer in this specific case is no, there wasn’t anything else useful found on the gun. In general, it is not possible to answer definitively the question of whether it is likely there would be any useful evidence remaining on the gun after it had been in water. A gun may have been cleaned, or the person who used it may have worn gloves, so there may not have been any useful evidence on the gun before it went into the water. If there was fingermark and DNA evidence on the gun then this would have started to degrade once it went into the water, and this would be more likely to occur if there was motion of any sort, such as tides or winds moving the water around. Many components of fingermarks such as sweat are water soluble, as is DNA, and so these would eventually be washed away. The length of time it would take for this to happen would depend on many factors, including the length of time the gun was in the water, the type of water (e.g. freshwater or saltwater), and the amount of the material that was transferred in the first place.

Another question that was raised a few times was about mobile phones. As you know, this case is based on a real case, and that case occurred in the 1980s, so there were no mobile phones involved. When we developed this course we tried, for the most part, to replicate what happened in the real case as closely as possible, to give you as realistic an experience as we could. For this reason, Mr Ward did not have a mobile phone. However, it is worth noting that if this case had occurred more recently and mobile phones had been as widely used as they are now, the investigators would have been able to get a huge amount of information from Mr and Mrs Ward’s phones, either using triangulation to determine where the phones had been located, or by accessing phone records to see who the individuals involved in the case had been communicating with. Similarly, as CCTV cameras were not so widely installed in the 1980s, there was no CCTV evidence available in this case.

You will note that when we introduced Mr Dougan into the case, he used a mobile phone, as we had updated this part of the story to reflect current times better. We have used a little bit of artistic licence in places to make sure that we are able to introduce you to the different types of evidence that we wanted you to see. For example, when it came to Mr Dougan giving the police a false identity, some of you asked why the police didn’t take his driver’s licence or note the registration number of his car. In reality the police officers would have done that, but by including this aspect of the storyline we were able to build in the investigative aspect of looking for fingermarks, and the searching of these against the database resulting in a new lead in the case when they were found to be linked to another identity. For the large number of you who asked about the timing of Mr Dougan’s fingerprints being matched with Nigel Lloyd’s prints on the database, there wasn’t anything particularly significant about this, and there wasn’t any breakdown in procedures. This just reflects the reality of these types of complex investigations, in which investigators have to deal with backlogs in forensic laboratories and it simply takes time to get evidence processed through the system.

Some of you have asked about the amount of blood inside the car and the GSR and I have touched on both of these in previous “Ask Laura” sessions.

One other subject that came up a few times was toxicology, asking whether drugs analysis could be carried out once the drugs had been consumed. Samples of blood, urine and hair can be taken and examined for the presence of drugs, and in a post-mortem other samples may be taken, such as the stomach contents or the vitreous humour of the eye, which is often used when bodies are very decomposed. Solid tissue samples can also be taken, including samples of the brain and liver. This analysis of drugs in biological samples is known as toxicology and there was no toxicology report on Mrs Ward reported in the case. Toxicological analysis can produce very important forensic evidence, and this is one major area of expertise that forensic scientists can specialise in. Unfortunately, we simply did not have time to cover every type of forensic evidence in six weeks, and so it was not possible to include toxicology in the course at this time.

Some of you mentioned the time discrepancy relating to the waiter’s evidence, and this has been raised in previous weeks. These time conflicts really just come down to human nature, as it is completely natural to not be able to remember to the hour exactly what you did on a given day. Timing inaccuracies in cases are to be expected, and our reconstruction of this case deliberately reflects the uncertainty over timings that investigators have to deal with in reality.

There were also a lot of questions about what Mr Ward said in interview with the police, what Mrs Ward knew about her husband’s affair, was an insurance policy taken out on Mrs Ward, etc. We wanted to focus very clearly on the scientific evidence in this case, and the way that forensic science was used to aid in the investigation. We therefore did not include any information about these types of questions as it was not within the scope of the course.

All that remains now is to say that I hope you enjoy the rest of the material in Week 6. The video revealing what really happened will be made available at 16:15 BST this Friday, 3rd April, and we are asking you to vote up to 16:00 BST on Friday for whether you think Mr Ward is guilty or not guilty. We really hope you will take the time to vote, and we would love to see lots of responses. I would also encourage you to vote according to your analysis of the evidence, and not on your gut feeling. This week we have been looking at a logical system for bringing together evidence and analysing it and thinking carefully about what it means from a scientific point of view. You should therefore focus on the science, work through it all logically and base your decision solely on what the evidence tells you. I really hope you have enjoyed the course, it has been a real pleasure interacting with you and reading all your comments. I have really enjoyed seeing how interested you have all been in the case, and how much discussion you have had about it each week. Thank you very much for joining us for the Introduction to Forensic Science MOOC, and don’t forget to cast your vote before 16:00 BST this Friday!

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This article is from the free online course:

Introduction to Forensic Science

University of Strathclyde