How do you solve a cold case?

We all love a good detective story. From the cosy crime escapades of Hercule Poirot, using the ‘little grey cells’ to unravel fiendish felonies, to the gritty world of Silent Witness, where a whole case can turn on the discovery of that vital bit of forensic evidence. In the real world, cold cases like Jack the Ripper or the assassination of JFK similarly excite people’s fascination with mystery and the need to know whodunit.

But what is it really like to work on a murder investigation? And how do the experts approach tricky cold cases?

Separating fact from fiction

“Programmes like CSI or Silent Witness are great for getting people interested in forensics, but they’re not that accurate to be honest,” says Sanita. “What they show is a glamorised version of reality, where you turn up to a crime scene in sunglasses and stilettos, and use technologies that don’t exist. Research carried out in the last few years suggests that only around 40% of the science you see in TV shows is actually real. The rest is made up.

“Crime dramas often show one person getting involved in everything. They will do interviews, collecting, processing and interpreting the evidence, and so on. That’s not how it works in practice. Everyone in the team has their own specific area of expertise that requires special training.”

Challenging this dramatized image, while giving students a real-world experience of investigations, is a key aspect of teaching in criminology-related disciplines at Derby. Academics have developed an initiative called ‘Justice for all’, where students in Law, Criminology and Forensics come together to assess real cases. Working with charities such as Murdered Abroad, students have looked at various ‘open verdict’ cases where British nationals have lost their lives in unexplained circumstances overseas.

“We recently examined the case of a British woman who died in Italy in 2014,” explains Tony. “Claire Martin was found with multiple stab wounds to her neck and the Italian authorities recorded a verdict of suicide. But the evidence clearly suggests it wasn’t. Under my guidance, the students identified a number of issues with the case and we’re now in a position to ask the Italian authorities to reopen the case as a murder investigation.

“One of the issues we identified was around the knife involved in her death. It was clear that the handle had been wiped clean after it was used and people who commit suicide don’t do that. Consequently, the forensics team could not find any DNA evidence. But there are forensic techniques that can find microscopic DNA traces in crevices around the handle, and these tests weren’t carried out at the time.”

Examining the body

As a forensic anthropologist, Sanita specialises in assessing human remains. She explains that there are strict policies governing how forensic officers carry out their work. “The scientific techniques have advanced significantly in recent years, and have given us greater confidence in the conclusions we can draw. But you still have to approach each case carefully, ensuring that you can demonstrate the continuity of evidence and a clear chain of custody. We have to be very strict on this, recording our actions and taking photos. If the case ends up in court, then the authorities need to demonstrate that the evidence presented hasn’t been tampered with in any way.

“I spend a lot of time working on archaeological rather than criminal cases, but the principles are the same. When it comes to assessing human remains, I will look to build up a presumptive profile of who the individual was. What sex were they? How old? How tall? How did they die? It can sometimes be quite challenging to find out information, so you look for ways to contextualise what you are looking at.

“A few months ago, I was called to assess a skeleton in a farmer’s field in Northumberland, which had been buried in a stone cist. Using carbon dating and knowledge of historical burial practices, we were able to date the remains to the Bronze Age, around 3,500 years ago.

“From there I carried out a morphological assessment, looking for visual clues on the skeleton itself. By looking at the development of the bones, I was able to assess that the remains probably belonged to a Caucasian man aged 17 to 21, who was between 1.72m and 1.79m tall. He had excellent teeth and symmetrical features, so he would have been a catch for the ladies. He must also have been a significant person in his community, because he was found buried with a horsehair blanket and a small decorated beaker.

“So it is possible to find out useful information using scientific techniques, even when the case is a very cold one!”

Elementary, my dear Watson

Working on cold cases is vital for students looking to gain industry experience, according to Tony, who is keen to pass on what he has learned to the next generation.

“The first step in investigating a cold case,” he explains, “is collecting all the material. You need to get hold of all of the evidence and do your own background research. Once you have done that, you are in a position to start thinking about what the evidence tells you. ‘Assume nothing’ is something we drill into people. You believe nobody and challenge everything.

“My students have also looked into the case of a young lady, Denyse Sweeney, who died in Goa. The evidence put forward by the Goan authorities suggested she had died of a drugs overdose, however the autopsy reports found no evidence of drugs. This is where we can help, taking an unbiased and objective view of the evidence, and forming a fresh picture of what could have happened. We found that Denyse had a substantial injury to her head that was inconsistent with the official suggestions. We highlighted our findings to the authorities and a new investigation was opened.

“You have to look for the anomalies in the case. What’s missing? What doesn’t feel right? So often it’s the little things that get overlooked that turn out to be the key details. That’s where fictional characters like Sherlock Holmes get really interesting. They notice the small details and build up a bigger picture from there.”

Solving a cold case

In many cases, agree Sanita and Tony, solving a cold case comes down to teamwork.

“You might get to a position where you have asked all the questions and still don’t have the answer,” says Tony. “That can be incredibly frustrating. But other times, intuition kicks in and you just know something is wrong with the evidence you have. By working collaboratively with a range of experts you can often help each other to unpick the truth.”

The experts

Tony Blockley is the Head of Policing at the University of Derby. During his 32-year career in policing, he worked as a divisional chief superintendent with Derbyshire Constabulary and, as Head of Crime, was responsible for investigating serious crime, homicide forensics, public protection, covert operations and managing intelligence across Derbyshire.

Sanita Nezirovic is the Programme Leader for Forensic Science with Criminology at the University of Derby. Sanita also works as a consultant for The Archaeological Practice Ltd, using her knowledge of forensic anthropology to assess human remains uncovered by archaeologists.

For further press information please contact the Corporate Communications Team on 01332 591891, pressoffice@derby.ac.uk or @derbyunipress

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