Garlasco’s crime is again in the center of‘media attention: in fact the news of New surveys made by the Carabinieri of the RIS to recreate one 3D mapping of the crime scene, the house in via Pascoli in Garlasco (PV) where on August 13, 2007 it was killed Chiara Poggi. For his murder he was definitively sentenced Alberto Stasibut the Pavia prosecutor has reopened the investigations After new data emerged that could also connect to the death of the victim too Andrea Sempliofriend of Chiara’s brother.
In particular, the Ris of Cagliari returned home Poggi with Scanner, laser rays and drones, with the aim of building a three -dimensional map of the place of the crime and better understand the dynamics of the murder, reconstructing in particular the different trajectories of the traces of blood.
But how they work Exactly these tools? The laser scanner, in particular, is able to measure the distance between the measurement tool and the surface of the object hit; At that point, a software Use images captured to reconstruct the three -dimensional map, with a Margin of error below millimeter for distances of 10 meters from objects.
These technologies were not available at the time of the crime, which dates back to 18 years ago. Today, however, the experts of the police have been able to use them to analyze the whole ground floor again, as well as the bathroom and the area of the staircase that leads to the cellar: the 3D mapping will serve the investigators to carry out the “triangulation»Of the traces of blood (not made at the time of the facts), analyzing with millimetric precision shape and trajectory of the sketches of blood.
How the 3D scanner laser scanner works
In general, that of the laser scan It is a technology already employed in engineering areas: these are tools that allow you to reconstruct the three -dimensional models of objects. In practice, the tool emits a large number of laser rays which affect the surfaces of the surrounding environment and, once reflected, go back in a time that is measured in an extremely accurate way. From the analysis of return times of each of these rays is possible, knowing the speed of the rays (which is the speed of light), to trace the distances traveled for each map map and consequently reconstruct the environment three -dimensionally.
The laser, therefore, replies point by point reality: in other words, the more the measured points will be, the greater the fidelity of three -dimensional reconstruction. According to the Carabinieri weapon, today there are laser systems capable of measuring up to 500,000 points per secondwith a margin of mistake minimum: it is a margin below 1 millimeter for scanned objects after about 10 meters.
The laser system is therefore able to measure the distance between the instrument and the surface of a object hit: once the data is collected, these come then examined from a special software, which uses images (captured in very high definition) to recreate the environment in 3D, mainly thanks to some topographic formulas which return coordinates in three dimensions (length, width and depth).
The advantages of reconstruction via laser scanner
There three -dimensional reconstruction It therefore allows operators to carry out more measurements accuratemanaging to determine with greater precision the impact corners of blood machines (of particular interest for the new developments of the case of Garlasco) or the trajectory bullets.
This technological tool, therefore, represents a great opportunity For the findings made by Ris and Scientific Police: among the advantages bigger there is precisely the possibility of examining and reconstructing the scene without the operator having to physically enter usthus eliminating the risk of potential contaminations or alterations of the place of the crime. The three -dimensional and high resolution reconstruction of the crime scene also allows reproduce And repeat The surveys, with the analysis of the crime scene which can also be carried out in later times.
The triangulation to study the shape and position of the bloodstains
According to the Ansa, in the case of the murder of Chiara Poggi the RIS of Cagliarispecialized in the use of the laser scanner: once the crime scene is reconstructed in 3D, the goal will be to carry out a “triangulation», A particular technique used to analyze with millimeter precision The traces of blood. This specific procedure is part of the “Bloodstain Pattern Analysis”, a forensic technique that studies the morphologythe distribution and position of the bloodstains.
At the time of the crime this triangulation had not been carried out: that’s why today all the tracks already found in 2007 are re -examining, which will then be included in the three -dimensional reconstruction in order to recreate the whole dynamics of the facts.
At the moment, however, it is not yet clear whether the three -dimensional mapping of the Poggi house will actually bring investigators to New conclusions On the dynamics of the crime: the Carabinieri of the Ris would have asked at least 60 days of time To complete the 3D analyzes and provide the results of the new surveys.
