DNA traces isolation from nail clipping material: a cold case in Ferrara

We report on the short tandem repeat analysis (STR), using QIAamp® ESS SE Plus Kit and performed on nail material collected from an exhumed body in order to verify the presence/absence of exogenous DNA belonging to the offender/s. Subject was born on june 27, 1970 and was last seen alive on september 30, 1988, at the age of eighteen, near a restaurant in province of Ferrara. The lifeless body was found without clothes at 7.30 am on september 30, 1988, a few kilometers away from the city, near the bank of Po river. The causes of death were identified in fratturative cranio-facial / encephalic lesions. These injuries, consequently the death, were produced by repeated blows to the head with a blunt body animated by high living force, and finally by the explosion of a stunning pistol gunshot in the left zygomatic region. The aggression was divided into several phases. During the first one, carried out using "natural means" by the aggressor/s, victim tried a defense. In 1988, investigations detected a suspect, a known criminal living near Ferrara. At that time, Court ordered the analysis of six bloodstain found respectively in the suspect’s car, on a stunning pistol and, finally, on an overall collected from suspect’s house. AB0 typing of these biological traces was negative and the suspect absolved. Because of new proofs, in 2015 Court reopened the case. In order to identify potential biological traces resulting from the aggression and placed under nails, twenty eight years later, Court, in relation to new identification techniques based on DNA, ordered the exhumation of the body in order to collect and analyze the nail material. DNA was extracted separately, using whole nail clippings and QIAamp® DNA Investigator Kit (Qiagen). In order to identify the DNA of the victim, two biological samples, collected from the body and represented by costal and femoral cartilage, were used as reference sample. Profiles interpretation strategy was dependent upon 3 independent PCR replicates (carried out for every nail sample) using the same DNA input (6µL) together with the proper use of extraction and amplification controls. The results obtained after the genetic analysis revealed the absence of exogenous DNA. Results proved the effectiveness and the robustness of this technology, contributing to make possible this identification approximately after thirty years since the death of the subject . At the same time, however, results cannot be exclude an exogenous DNA placing under nails samples originally. Therefore, technical evaluation of the laboratory data must consider any exogenous DNA degradation and, consequently, time elapsed since death to exhumation, and, finally, operations carried out before burial. All of these variables contribute to cellular degradation resulting in a complete DNA cleavage. Surely, application of DNA analysis at the time of murder would have greatly enhanced the chance to identify potential DNA traces of the offender/s.