Fulvio Cruciani, professor of Human Genetics and Forensic Genetics at Sapienza University and editor of the Science&Crimine series, what do you think of the wonders that can be seen in certain fiction, how much do they have to do with reality?
«Fiction sometimes exaggerates, but the gap with reality is narrowing. We are making enormous progress in all areas of forensic science, with innovations that have been real game-changers in the fight against crime.”
Footprints, tracks and clues. Science protagonist at the crime scene
by Luigi Gaetani
For example?
«In my field, forensic genetics, a decisive turning point dates back decades ago: PCR, which allows us to multiply the quantity of DNA found, even in minimal traces, at the crime scene. So now we can also analyze the DNA released by the simple contact of a person with an object. More recently, genetic profile databases have been created, which collect on the one hand tens of thousands of DNA profiles of people arrested for certain crimes, and on the other hand the DNA profiles found on the finds. Thus we can see, for example, that the DNA found at the scene of a murder in Italy belongs to a person arrested six years later in Austria. And again, from the DNA of an unknown person it is possible to trace his appearance (especially the color of his skin, hair and eyes), and even his age.”
What does all this information tell us for the purposes of the investigation?
«The genetic profile tells us if a DNA found on an artefact belongs to a certain person. But it does not give us the certainty of having identified the culprit: the DNA of a suspect can also be found at the crime scene for reasons not linked to the crime. So many other considerations are needed, so many other disciplines are crucial in forensic science, which give us the framework to contextualise what we observe at the crime scene. The analysis of which is in fact the first volume of the series.”
Were there also glaring errors?
«A famous one, in the USA, was that of Glenn Woodall, acquitted after an unjust conviction for kidnapping and rape, arrived at by virtue of a series of clues that included the limited genetic analyzes of the time, which were also badly conducted, but even deliberately falsified by an expert. Then PCR made it possible to analyze the DNA of the rapist’s sperm and demonstrate his innocence.”
And a particularly difficult case solved?
«Also in the USA, the so-called Golden State killer, Joseph James DeAngelo, who committed dozens of serious crimes decades ago, was recently identified. Only in 2018 did the genetic profile of the unknown criminal turn out to be similar to that of a distant relative of DeAngelo, found in the database of one of those commercial companies that offer to reconstruct one’s origins. From there, we then went back to DeAngelo.”
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– 2024-04-03 01:55:23
