Meet the scientists!

Forensic science is a very complicated business with lots of different specialist subjects. My area of expertise is the interpretation of body fluids and DNA evidence.

I deal mostly with criminal cases and the aim of my work is to see if the body fluids found on items such as clothing or other objects used in a crime, can help to tell the police something about what happened and who was involved.

The position and appearance of a body fluid stain such as blood, can tell us a lot, for example, how a weapon was used, such as in this picture, where the direction of the blood spots shows that the metal pipe was used to strike a person more than once:

Other body fluid stains such as saliva, might not be as easy to see, so I can use chemical tests and special lighting conditions to help find them on an item. I might also need to look down the microscope to look for specific types of cells such as these sperm (magnified here 400 times):

Once the body fluid stains have been found, I can use DNA profiling if I want to try to find out who the body fluid was from. A person’s DNA profile looks like this:

DNA profiles like this one can be compared to a reference DNA profile from a suspect, or compared to The National DNA Database which holds the profiles of everyone who has been arrested for a crime.

Finally, when all the results are in and all the comparisons done, I write my results in a statement which is sent to the investigating police officer and to the crown prosecution service (CPS.) CPS will later decide whether the case should be heard at court, and I may have to attend to explain my evidence to the members of the jury. 

Whilst working for the Forensic Science Service, some days might be spent entirely at my computer, writing up my reports and statements, whilst on other days I might be working in the lab on an item examination or checking an unusual finding such as this tyre mark on the leg of a pair of trousers, found using a special light called a ‘crime-lite ML’.

Occasionally, if an urgent case arrived, I might have to drop everything and start to think about my strategy for that case. Whilst on call, I might have to work on urgent cases outside of normal hours by going to the lab to help with an examination or by giving advice to a police officer over the phone. The latest I’ve worked on an urgent case is until about 3:30 in the morning. After that I felt exhausted! Here’s a couple of pictures to show the clothing I’d usually wear before going into the lab (yes it’s me in the silly hat) and the bench where I was working.

On other days, I might be giving forensic awareness training to police officers and doctors, or attending a case conference where all the police officers, scientists and sometimes the lawyers working on a case, meet up to discuss where the case is up to and what we still need to do. At other times, I might be at crown court waiting to give my evidence – and it’s the waiting that’s the most nerve-racking part.

Since leaving the FSS at the end of March, my days are equally unpredictable. At the moment, I’m busy writing training courses for other forensic scientists and police officers, articles about recent developments in forensic science, and marketing my company which provides independent forensic advice to the criminal justice system.  In summary, just like working for the FSS, I’m never sure what might happen when I answer the phone, which can make planning my day somewhat tricky!   

This is something I’ve been thinking about for a while now. I’d like to create a workshop for school children in my local area, in which they’d be able to carry out experiments and learn about forensic science. This might include looking at hairs or different cell types down the microscope, throwing blood around to look at the patterns made by impact, making tyre prints and footwear marks to see their unique features, and looking at the different effects of damage to pieces of clothing. I’d like to put the money towards buying equipment for this project such as a microscope, a large tent for the ‘blood pattern analysis’ experiments, and lots of protective clothing, because forensic experiments can get messy!