Awarded with a medal for his body of work on fingerprints, Christophe Champod talks about his career and his field of research, which he probes on the basis of probabilities.
A bottom shelf provides a discreet home for his various awards. Of which he has many. We have barely entered his office when Christophe Champod picks up his most recent: the Henry Medal he received in Manchester on 31 March. This honorary award has only been awarded four times since 2001 by the British Fingerprint Society and recognises the entire body of fingerprint-related work by Champod, a full professor at the School of Criminal Justice (ESC) at the University of Lausanne. ‘Although my research has made me a bit of a heretic in the field,’ he points out with a mixture of surprise and delight.
For over 25 years now, the academic has been looking at statistical issues relating to the identification of (mostly papillary) traces (see below) and footprints. ‘From the very early days of forensic science, it was thought a trace might be enough to identify or rule out a suspect.’ This is a rather binary way of looking at things, and Christophe Champod has introduced a more nuanced approach with large helpings of statistics.
‘I almost got laughed out of town when I raised the subject of probabilities, and this was only ten years ago,’ he confesses, while rummaging through his drawers for a case he is currently working on.
For the courts to decide
There are two images on the table. One shows a finger trace found on a packet of drugs. The other shows a suspect’s fingerprint records, the reference document containing prints of their ten fingers. Small circles indicate areas where a first expert found matches.
His nose almost touching the two photographs, Christophe Champod points out that certain ridges do match, as well as places where lines comes to an end. But is this information enough to identify the suspect formally? What is the likelihood that another person, purely by chance, might share the same characteristics? ‘Even these days within the profession, people feel it’s up the expert to decide in all good faith. Yet thanks to the development of IT tools, nowadays these elements can be measured and quantified.’
So should it be up to judges to interpret the probability of potential errors? ‘The risk of a trace being linked with someone’s print quite by chance is extremely low – let’s say one in a billion – and most laboratories simply state they have identified who the trace belongs to. Now although the risk of error might be tiny, it does exist. As far as I’m concerned, it’s up to the courts, and not academics, to decide.’ This is rather a difficult message to get across in a discipline where certainty is everything. ‘Fortunately, things are changing. It is important to realise that we, the experts, are establishing probabilities rather than facts.’
According to the professor, it is a question therefore of remaining vigilant and critical towards reports produced by laboratories. ‘But don’t go thinking there’s a one-in-two chance of making a mistake when comparing prints,’ he insists. This issue is a core aspect of the MOOC (Massive Open Online Course) set up by Christophe Champod in collaboration with several other forensic science specialists at the School of Criminal Justice.
Available to everyone free of charge from autumn 2017, this online course mainly features testimony from victims of miscarriages of justice and their relatives. For example, Christophe Champod got the chance to interview the father of a Scottish policewoman who was wrongly accused of leaving a finger trace at a crime scene. A case the specialist knows only too well, having been involved in the inquiry which finally proved the young woman to be innocent. ‘The results are there,’ he says, pointing to a blue file as thick as a dictionary.
Experts with an unfair advantage
In addition to his research work, Christophe Champod devotes 20% of his time to actual cases, including some abroad. And he believes this judicial work as a commissioned expert makes a vital contribution to his teaching and research. ‘Besides, I get bored if I don’t have a case on the go,’ he admits with a laugh.
The stories he tells with such conviction and enthusiasm reveal something of an uneven playing field. ‘The defence often has less access to scientific resources. Sometimes due to lack of money,’ he explains, before starting to read a handwritten letter that landed on his desk that very morning. It is a cry for help from someone convicted of a crime, begging the professor to examine the expert evidence in their case. ‘Of course I’ll take a look. It is important to see what this family needs.’
Sometimes, the problems accessing scientific evidence is also due to a lack of expertise on the part of judges and lawyers. Realising this, Christophe Champod founded a forensics consultancy start-up while studying for his doctorate at UNIL in the early 1990s. He did this with Franco Taroni, a colleague and flatmate from the time, who is now a professor at the School of Criminal Justice too. Working together, the pair offered to help lawyers correctly assess the technical reports they were receiving in order to prepare for trials.
A thirst for knowledge
A future in research or even going to university were not something this shopkeeper’s son could take for granted. As a child, he struggled with school at times and had to resit the entrance exam that prepares pupils for entry to grammar school. ‘My teacher made me work hard to pass the examination. He told me about his daughter at university, and it all sounded fantastic.’ At the time, the academic often accompanied his mother, who worked as a cook and maid, to her employers’ houses. ‘These were highly educated people who knew about lots of things, and they had a big influence on me too. But without the encouragement and support of my parents, I would never have continued my education.’
After leaving Neuchâtel in 1986 to start his degree at UNIL, Christophe Champod admits he found things very hard at first in Lausanne. ‘The place was huge, and I didn’t know anyone.’
A student in the ‘first intake under Professor Pierre Margot’, who was appointed Director of the Institute of Forensics and Criminology the same year, Christophe Champod was offered an assistant’s post upon completion of his studies. ‘There were six of us, and we shared out thesis topics among us,’ he recalls with a smile. He then started to concentrate on fingerprint statistics and developed a passion for computer programming. There was no turning back, and he was finally appointed full professor at UNIL in 2003, following a four-year spell in England.
‘The terms “print” and “finger” are often used rather indiscriminately. First, the word “finger” is too restrictive, because the little ridges, formed by papillae, on our fingers can also be found on the palms of our hands and the soles of our feet,’ points out Christophe Champod, who prefers to talk about ‘papillary’ traces.
Second, it is important to make a distinction between prints and traces. ‘The word “prints” is used to refer to impressions obtained under standardized conditions, such as when you’re arrested and the police cover your ten fingers with ink and roll them across a sheet of paper.’ By contrast, a trace is a mark left by papillary crests without any kind of control. So at a crime scene, investigators take traces (of fingers or palms) as opposed to prints.