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Are we experiencing an exciting turnaround in the “Rebecca” case? For four years, the disappearance of Rebecca Reusch has not let go of the whole of Germany. Now the police have visited the brother-in-law’s apartment again – with surprising findings. Christian Matzdorf, professor of forensic science with a focus on forensic science, explains in an RTL interview why there are new tracks.

Does a search warrant mean that there really are new findings?Matzdorf: The demands on a search warrant in connection with a house search are very high. This means that we can assume with a high degree of certainty that there were indications that this house search would again lead to a result relevant to the investigation. Otherwise the competent judge would not have issued this decision.

Among other things, it should also be about a bathrobe belt. This has not been discussed in previous years. How can it be that years later such a detail suddenly becomes relevant again?Matzdorf: You have to see these things against the background of criminal activities. If new clues come up in the course of the investigation, it is quite possible that individual aspects that were already known beforehand, including traces, such as a bathrobe or a missing belt, suddenly take on a completely different meaning. This is similar to testimonies: We may have a clue from a witness that doesn’t seem relevant at first. If more information is added, it can take on a new relevance, like a puzzle whose pieces are constantly changing and reassembling.

How likely is it for you that this case will still be solved? Matzdorf: It is not possible to determine the probability in percentages. But we know of a few comparable cases in the history of the Federal Republic of Germany, where, even after 20 or 30 years, a person who has disappeared, usually dead, has still been found. In this specific case, we still hope that this missing girl will be found alive. The hope is very small, even the public prosecutor says so. But we can still assume that there is a high probability that this case will be solved and that mortal remains may then be found.

What can you still find at a potential crime scene after four years? Matzdorf: Forensic technology has now progressed so far, also in the field of DNA analysis, that it is practically impossible to commit an act at a crime scene without leaving traces there become. This also applies to a certain type of trace over a long period of time, so that one can say: even after four years it is still possible to find something. Of course, the probability decreases and the probative value of the traces changes over time. In this respect, four years is a long time.

What role does technical progress play?Matzdorf: Technical progress is both a curse and a blessing in forensic science. Today we have the opportunity to evaluate and analyze a single skin scale in such a way that we can determine a person’s DNA profile from it. On the one hand a great advantage, on the other hand of course also a high demand on the forensic technical work at the crime scene and on the forensic technical analysis work in the laboratory, to examine the traces cleanly and differentiated and to evaluate them conclusively in the investigation process.

Can such searches also increase the pressure on a possible perpetrator independently of the traces found? Matzdorf: A search like this must always be viewed in the overall criminal strategic context. That is, the search itself is a tactical measure that may be warranted by new intelligence. But of course it can also play a role in the investigative strategy and of course this creates new pressure and possibly a new situation in which the person who is seen as a suspect then has to behave again. And that can of course mean that the results lead to the urgent suspicion being substantiated.

Christian Matzdorf is a professor of forensic science with a focus on forensic science at the Berlin School of Economics and Law (HWR).