Stability of human α-salivary amylase in aged forensic samples.

The unequivocal tissue identification in forensic casework samples is a key step for crime scene reconstruction. Just knowing the origin of a fluid can sometimes be enough to either prove or disprove a fact in court. Despite the importance of this test, very few data are available in literature concerning human saliva identification in old forensic caseworks. In this work the stability of human α-amylase activity in aged samples is described by using three different methods integrated with DNA profiling techniques. This analytical protocol was successfully applied on 26-years old samples coming from anonymous threat letters sent to prosecutors who were working on "the Monster of Florence", a case of serial murders happened around Florence (Italy) between 1968 and 1985.