A crucial element in solving the Garlasco murder is the ability of forensic genetics technologies to produce reliable results. But it is also important that judges are aware of how they are used by Andrea Monti – Initially published on MIT Technology Review Italia
Ever since Sir Alec Jeffreys put his research on genetic markers at the service of the British police in the 1980s to solve a murder case, forensic genetics has been a fundamental tool in the toolbox of investigators and defence lawyers. Over time, methods and tools have become increasingly accurate, but the “DNA wars” waged since the early days in American courtrooms over the reliability of results still provide a clear example of a fundamental need to ensure the sensible use of forensic genetics: the ability of the parties to understand the results presented to them, even — and especially — if they do not coincide with the investigator’s or judge’s view of the case.
A paradigmatic case in Italy is the Caffarella rape committed in 2009, in relation to which it is worth quoting verbatim the statements made by the then Rome police chief in the article “Stupro Caffarella, ‘L’accusa regge’ (Caffarella rape, ‘The charge stands”) published on Repubblica.it on 4 March 2009: “We were the ones who requested the DNA,” emphasised the police chief, “because we are the first to want transparency, and we were the ones who took a saliva sample from the younger of the two Romanians arrested immediately after his confession,” he continued. ‘While admitting that DNA is the ultimate proof, we still believe in the validity of the entire prosecution case. In other words, adherence to the investigative theory prevails over scientific evidence, despite the fact that the latter excludes the possibility of linking the biological traces to the suspects.
Another equally paradigmatic case, described as the most serious miscarriage of justice in Japanese history, is that of Hakamata Iwao, who spent almost fifty years on death row in a Japanese prison before being exonerated in 2025 thanks to new genetic analysis techniques.
These two examples, although distant in time and space, are united by the inability of the parties involved in the trial — and the judge in particular — to develop a critical approach to the role of science in the trial and, in particular, to the logical consistency of the results presented in the proceedings.
To explore these issues in greater depth, MIT Technology Review met with Giuseppe Gennari, a judge at the Court of Milan and author of monographs and articles on forensic genetics and scientific evidence, and asked him whether, and in what way, the Garlasco case is paradigmatic.
What tools were used in the 2014 genetic analysis and what are their technological limitations?
The 2014 expert report used the Prepfiler Forensic DNA Extraction Kit (validated in 2006), which is still valid but not optimal. The quantification phase was omitted, probably due to the absence of Real Time PCR, which was already a recommended standard at the time. The AmpFlSTR Yfiler PCR kit was used for amplification, which is capable of amplifying only 16 Y-STR loci, while the PowerPlex Y23, which amplifies 23 with greater sensitivity and accuracy, had been available since 2013. Sequencing was performed with an ABI PRISM 310, a forerunner in its class (1995), surpassed by models such as the 3500 Genetic Analyzer (since 2010), which offers greater throughput, sensitivity and background noise reduction.
Why does the choice of equipment have a critical impact on the reliability of DNA analysis?
The effectiveness of genetic analysis depends on several parameters: sensitivity, reproducibility, analytical resolution and artefact reduction. Outdated equipment generates a higher risk of allele dropout, stutter peaks and incomplete profiles. In addition, modern kits use more robust reaction chemistries optimised for degraded or mixed samples, improving the likelihood of obtaining interpretable profiles even under complex conditions.
What international standards were already in place in 2014 to ensure the quality of forensic genetics laboratories?
EU Council Decision 2009/905 already required forensic laboratories involved in DNA analysis to comply with the ISO/IEC 17025 standard. In Italy, Law No. 85/2009 established that only genetic profiles generated by accredited laboratories could be entered into the national DNA database. These standards imply the obligation of internal validation, participation in proficiency tests and the use of documented SOPs (Standard Operating Procedures).
What is meant by internal validation and proficiency tests and what is their practical relevance?
Internal validation consists of on-site verification of the key parameters of each methodology in use: sensitivity, specificity, repeatability and reproducibility. Proficiency tests, on the other hand, are blind tests provided by third parties, which allow the performance of the laboratory to be assessed on standardised samples. Both are fundamental requirements for maintaining ISO/IEC 17025 accreditation and serve to ensure that every analytical result is reliable and defensible.
What alternative options did the court have to ensure state-of-the-art genetic analysis?
The court could have relied on one of the three accredited laboratories already present in Italy in 2014, or imposed an obligation to use equipment that complies with international standards. It could also have requested evidence of participation in Proficiency Tests, or consulted an external scientific committee to validate the choice of expert. Instead, the approach adopted was based on personal trust without objective checks, which undermined the robustness of the entire expert report.
In systemic terms, what does the Garlasco case reveal about the technological culture of the Italian judicial system?
The case highlights a persistent disconnect between scientific and technological knowledge and legal practice. Experts are often selected according to non-technical criteria, with little attention paid to the equipment they use or quality certifications. In addition, there is a structural lack of technical training among magistrates and lawyers. This leads to an underestimation of the factors that determine the soundness of scientific evidence, with serious repercussions on the rights of defendants and the credibility of the trial.
Does this disconnect only concern forensic genetics or is it a more general phenomenon?
No, it is an absolutely general phenomenon and concerns both traditional scientific evidence, which is often completely lacking in “scientificity”, and new applications presented as absolutely reliable but not rigorously verified.
In the case of the murder of Lidia Macchi, the alleged murderer – who was eventually acquitted after spending three years unjustly in prison – was convicted in the first instance on the basis of a psychological report that claimed to have extracted a confession from the text of a poem. Then there was the “lie detector” phase, when several Italian courts believed they could decide who was lying and who was not on the basis of a test called the IAT. The problem is that the scientific literature supporting the test was questionable, to say the least, but the judges did not notice this because they had no epistemological expertise.
So what can we expect for the future?
Unfortunately, nothing good. Magistrates still have no specific training in science, and I don’t mean specific techniques, but scientific methodology, what defines data as verified or not, the criteria science uses to measure itself. The school responsible for updating Italian magistrates does not seem effective. It merely offers a non-compulsory annual course for a few dozen magistrates, bringing together experts who talk about this or that piece of evidence. But there is no compulsory, structured programme to educate magistrates in the basic rules of science. This is serious because in some areas – and here I return to genetics – the level of complexity of certain investigations is such that it is already completely beyond the real control of today’s magistrates. When magistrates lose control of their decisions, it is the very legitimacy of the judicial system that is called into question.