FORENSIC SOIL ANALYSES APPLIED TO THE LAURA M. HOMICIDE CASE

In Italy soil analyses applied to forensic cases began to be adopted at the beginning of the eighties in an effort to solve serious cases of kidnapping. The Soil Laboratory of the Polizia Scientifica, which is the forensic laboratory of the Italian State Police, performs soil analyses in all cases in which soils can provide useful legal evidence to the investigation.

The purpose of this presentation is to provide an overview of soil analytical procedures we use in Italy. A homicide case will be presented in which soil analyses was determinant in solving the case. The Police found the body of a young woman, Laura M., in her cottage. Neighbours reported that the day before they heard the woman quarrelling with her boyfriend. A judicial site survey was conducted at Laura's cottage during which four soil samples were collected: from the shoes of the victim, from a shoe mark near the body, from the car and shoes of the Laura's boyfriend. The purpose of investigators was to collect and study soil traces in order to link Laura's boyfriend with the criminal event. Soil analyses performed to solve the case were the following: morphological observation, grain size separation, petrographic characterization with thin sections, X-ray diffraction, S.E.M. analyse and thermogravimetry.

The results demonstrated not only the reliability of the analytical procedures, but also how important it is to carry out the survey and collect evidence samples with precision and accuracy.