SNV
Story 8

SNV Story No. 8: Zurich Forensic Science Institute

The truth about forensic sleuths

Most of us, if we’re honest, have gleaned most of what we know about forensics from fiction. As a result, we tend to associate forensic science with poorly-lit examination rooms, oddball characters and of course, the obligatory corpse with a label on its toe, waiting patiently in its refrigeration unit for someone to uncover the secrets it hides. The reality of forensic science – and especially the division of roles between forensic scientists and the police – is rather different, with many more layers. As Dr Michael Bovens of the Zurich Forensic Science Institute (Forensisches Institut Zürich – FOR) so humorously puts it: “The skills you often see a single, fictional “supercop” display are actually distributed among many of us who work here. We aren’t quite as quick, or quite as photogenic, but we definitely drink better coffee!” There is a huge range of tasks that might need to be done on any given day, so every day is different. Sometimes you will be securing evidence at the scene of an incident, sometimes you will be analyzing and evaluating in the laboratory, and sometimes you will be reporting findings to the investigating authority, to name just a few of the tasks.

The Zurich Forensic Science Institute (FOR) is very proud of the quality of its work. As the leading forensic science institute in Switzerland, authorities from other cantons and even other countries often seek the support of FOR. The Swiss Association for Standardization (SNV) spoke to Dr Michael Bovens about the institute, its work and its involvement in the standardization committee ISO/TC 272.

Since 2015, FOR has been a member of the committee for the development of standards in the field of Forensic Science in ISO/TC 272, which began its standardization work in 2013. The key motive for participating was to be able to influence the design of the standard. After all, the standards set here would affect the institute’s daily work going forward. It was crucial to balance maintaining high quality with keeping the entire process practical and feasible. In other words, what is theoretically possible or possible from a purely academic point of view is not necessarily an improvement in practice, nor is it necessarily customer-oriented. Dr Michael Bovens illustrates the point with a simple image: «There are many possible ways to eat soup, but not all of them are efficient or effective. A spoon is definitely preferable to chopsticks.»

Standardizing the process, not the discipline
The aim of the ISO/TC 272 standardization committee is to publish a series of standards on forensic sciences in five parts: laboratory and field-based forensic science techniques and methodology, the detection and collection of physical evidence, subsequent analysis, interpretation of results and reporting of results and findings. Some parts of the series of standards have already been adopted. The current plan is to finalize the remaining parts that are still in development by 2023.

Image: The five parts of the standardization work on forensic science described in ISO TC 272.

Michael Bovens, Doctor of Chemistry, Chief Scientist of FOR and Chairperson of the ENFSI (European Network of Forensic Science Institutes) took us through the individual parts of the ISO 21043 series of standards.

Definition: Who’s right? The fingerprint examiner or the chemist?
When specialists from different fields come together to discuss something, misunderstandings and miscommunications often occur. One of the reasons for this is that each person approaches the question from their own specialist angle. Each expert has their own vocabulary, their way of interpreting things and their own understanding of the problem. Attempting to reach a consensus on terminology often leads to lengthy discussions. The committee experienced this first-hand when establishing its terminology. Let’s take the term «identification» as an example. What do you think of when you hear this word? For a fingerprint examiner, a fingerprint has been identified once it has been matched to a single person. For a chemist, a substance (such as cocaine) has been identified once it has been unambiguously assigned to a particular classification using instrument-based analytical methods. The unique or individual properties of the specific sample in question are not of interest here. Classification is sufficient. The individual properties of a single sample only come into play in material recognition when there are questions about whether samples might have a common origin – whether they might come from the same production batch. With that in mind, it is easy to see how discussing and verifying various «definitions» can take a few years, especially when it comes to topics related to investigation requirements.

Image: Taking a random sample from an item seized as evidence to detect narcotics. (Source: FOR)

Recognition: guided by traces, not by hunches
Securing evidence on site is the first and most pivotal element in the evidence chain. Every trace on the site, no matter how small, must be found, recorded, properly labelled, secured, transported and stored. Throughout the process, it is vital to ensure that nothing is contaminated or destroyed. The task is to bring the material that bears witness to the crime back to the laboratory with its original qualities completely intact. The Zurich Forensic Science Institute (FOR) always attends a crime scene with at least two experts to secure traces. This is to ensure that traces are secured in the most objective way possible. The aim is to prevent anyone from being misled into jumping to conclusions due to the pressure of external expectations. The forensic scientist is responsible for the trace, which is the material – the factual evidence – that builds up a plausible picture of a course of events. Tasks such as reading between the lines, picking up on moods and emotions, talking to witnesses and interviewing suspects to establish their picture of the course of events are the responsibility of the investigators, the investigating authority in charge of the proceedings, and lawyers – these tasks are not part of the forensic scientist’s remit.

Image: Reproduction of traces made by polygrip pliers implicated in a crime on sheet lead for the purpose of comparison in a tool trace investigation. (Source: FOR)

Analysis: What makes a result a result?
Once the evidence has been transported to the laboratory, the next step in the process begins: analysis. The time this takes varies depending on the question that needs to be answered. Analysis produces results that are in themselves sufficiently meaningful and of sufficient evidential value that they can stand on their own merit and do not need to be viewed in context – apart from the tolerances that need to be taken into account. For example, identifying and, if necessary, the determining the concentration of a narcotic in a sample may in itself be sufficient for proceedings to go ahead.

After a road accident, for instance, any residues of narcotics on the driver’s clothes or in their urine can be detected and unambiguously classified. However, this still does not tell us much about the driver’s driving ability at the time of the accident, i.e., the actual effect of the narcotic on this particular person at that time. In such situations, results can no longer stand on their own merit. They need to be viewed in context – and that context is often controversial. Forensic scientists call the context the «underlying hypothesis». That task here is to assess how well the results that have been obtained fit the various hypotheses. This approach to analysis is explained in the fourth part of the series of standards.

Interpretation: when the result of the analysis is not sufficient in and of itself to answer the question that needs answered.
This is usually the case with complex series of events that can no longer be conclusively reconstructed. There are various possible explanations for the final result. In such cases, the results from the material analyses act as «silent, objective witnesses» and the task of the forensic scientist is to assess how well the results obtained match the various hypotheses.

Image: Powder deposits: combustion residue that comes out of a gun when it is fired. (Source: FOR)

Reporting: when non-lawyers write for lawyers
At the end of an examination, the information that has been gathered needs to be documented and packaged in a concise report. It is important to remember that the target audience for these reports – in Switzerland, this is the judiciary – speaks its own language, which is not necessarily the same as the language of forensic science.

The Zurich Forensic Science Institute (FOR) entrusts its employees with the entire process chain as far as possible. The person who is called to the scene of the crime to secure the evidence also writes the report at the end, and this report serves as the basis for decisions in court. Neutrality and objectivity are paramount. Forensics is not there to acquit or condemn, but only to describe, analyse and evaluate results in the light of hypotheses.

When drafting standards, it is important to bear in mind that the countries participating in the standardization process have different penal procedures. For example, there is the «adversarial system» used in Commonwealth countries (such as the UK, Australia and New Zealand) and in the USA, and there is the «inquisitorial system» used in Switzerland and other continental European countries. Although we now have state-of-the art instruments, new technologies and even artificial intelligence, human beings are still responsible for decisions made throughout the entire forensic process, from securing evidence on site to pronouncing the judgement. The people who work in forensics have always been the most valuable problem solvers in the process. Without people, the case simply doesn’t get solved.

It’s therefore easy to see why Bovens loves his job as a chemist and the «highest-ranking forensic scientist in Europe». This work is anything but everyday. And when it all gets a bit too much, the 25 km cycle home provides the perfect way to switch off.

The fingerprint as an identifier
The skin on the inner surface of the hands and feet is anatomically different from the skin on the rest of the body. It has papillary ridges (skin ridges), but no hairs, sebaceous glands or scent glands. The papillary ridges are raised lines that increase adhesion and grip. The sense of touch is also located in the papillary ridges. Therefore, fingerprints and handprints are images of these papillary ridges that occur because we leave imprints composed of sweat and other secretions on objects with our fingers and hands when we touch them. Special methods can be used to make these residues visible at the crime scene or on seized evidence. Depending on where the trace was secured, on the specific circumstances and on the statements given, a fingerprint identification may exonerate or incriminate the person in question. In 2020, FOR matched over 1000 visualized fingerprints to an individual or a trace – a significant increase in the number of hits compared to the previous year, which also had more hits than the year before it. The number of fingerprint hits now exceeds the number of DNA hits, which clearly demonstrates that the fingerprint still holds a unique position in forensics, even in the age of DNA.
(Source: FOR, Annual Report 2020)

Image: A fingerprint is carefully prepared to ensure optimal quality for identification using the comparison database. (Source: FOR)

Profile: the Zurich Forensic Science Institute – Forensisches Institut Zürich (FOR)

The customer: Zurich City and Cantonal Police, police corps and bodies responsible for legal proceedings in the cantons
The future: as of 1 January 2022, the Canton and City of Zurich will establish FOR as an independent institution under public law.
The head: Thomas Ottiker (since 1 September 2017)
The employees: 162 in total (63 at Zurich City Police and 99 at Zurich Cantonal Police – 122 men and 40 women, average age 49.1 years)
The professions: chemical laboratory assistants, physicists, chemists, accident analysts, secretaries, engineers, gunsmiths, weapons disarmers, biologists, phoneticians and many more.
Scope of work in 2020: almost 28,000 assignments (including police records services and ID checks) and more than 3,300 forensic investigations

(Source: FOR, Annual Report 2020)

The many faces of forensics
Case reports from the FOR annual reports of 2018 to 2020

FOR prepared five expert reports on the extensive investigations into the Ju-52 plane crash in August 2018. The specialist from the 3D Centre Zurich (3D-Zentrum Zürich – 3DZZ) conducted complex 3D evaluations of video recordings and photographs taken by aircraft occupants and witnesses in order to reconstruct the final phase of the flight and the crash.

A stolen queen! In the wine-growing region of Zurich, a beekeeper noticed that 14 of her 16 queen bees had disappeared. They could only have been taken by someone with knowledge of bees and with suitable equipment. A FOR employee who keeps bees as a hobby was assigned the task of securing evidence. The search for traces proved fruitless – not surprising since beekeepers of course wear protective clothes all over – but local media covered the story sympathetically. The 14 bee colonies could not survive without their queens, resulting in around CHF 3500 worth of damage.

Surveillance cameras captured an arsonist setting a fire. His claim that the recordings had been manipulated to frame him was refuted thanks to an expert opinion from the image forensics department.

A photofit of Leonardo da Vinci needed to be created for a new biography on the star of the Renaissance. During creation, the author (a Leonardo da Vinci buff) acted as the «eyewitness», while FOR’s Dr Grit Schüler worked in cooperation with the University of Zurich to show what Leonardo da Vinci might have looked like around 1490 as a beardless man in his late thirties according to the evidence.

Someone in a stolen tractor ran over a Robidog dog waste bin and some other items and caused additional property damage. The end of a joint led the police to the juvenile culprit. He had missed the last train so he procured another means of transport for himself.

In a collaborative, cross-team effort, the chemists of FOR solved a mysterious prison break. The analysis of traces on the broken bars revealed residues of a strong acid applied by the prisoner to cause the iron to rust and become brittle.

A female corpse proved difficult to identify. DNA tests and other investigations yielded no clear result. With the help of morphological image comparison and superimposition (3D skull reconstruction), it was possible to establish the identity of the elderly lady.

(Source: FOR, Annual Reports 2018–2020)

Dr Michael Bovens: FOR’s «Foreign Secretary»
«Looking back on my 25 years in police forensics, I never could have imagined that my doctorate in chemistry would lead me on a career path that provides such variety. When I became Head of the Chemistry Division and later Head of the Central Analytics Department, I quickly had to expand my professional network to other countries. These days, I often travel abroad as the sole representative of FOR in this exciting field of forensics. When I was appointed «Designated Chairperson of the ENFSI» at the end of 2017 (and was subsequently elected to the position in May 2018), I was given responsibility for the European Network of Forensic Science Institutes (73 laboratories in 39 countries). I’m honoured to be recognized as «Europe’s highest-ranking forensic scientist» and by the trust that has been placed in me. As the Chairperson of the ENFSI, I will take the lead on ENFSI business for another two years together with the Executive Board. It’s a wonderful challenge to act as Chief Scientist and as a kind of «Foreign Secretary» for FOR at the same time – it provides plenty of variety.» – Dr Michael Bovens
(Source: FOR, Annual Report 2019)