Application of biochemical and X-ray diffraction analyses to establish the postmortem interval.

The determination of the date of death from bone remains is of scientific interest but also has important legal implications. The establishment of the postmortem interval (PMI) is a very complex problem because of the great number of intrinsic factors that may alter the normal course of postmortem change, such as the age, sex, constitution and previous physiological and pathological states of the subject, and external factors. In order to evaluate the utility of X-ray diffraction and the measurement of some components in dating bone remains, a total of 69 long bones from 69 different cadavers (41 males, 28 females) with a mean age of 68 years (S.D.=17.6, range 12-97) were used. The bones were removed from cement tombs of Murcia Cemetery, where they had lain for documented times of between 7 and 54 years (S.D.=11.6, mean time 17.6 years). We have studied potassium, sulphur, nitrogen, urea, total protein, phosphorus, and some X-ray diffraction (XRD) parameters related to the degree of crystallinity of the mineral component in medullar and cortical bone zones to establish which of the two provides the most useful information for calculating the PMI. In the overall analysis of our data, we believe that the use of both XRD and biochemical analyses (especially of urea, potassium and sulphur) particularly in the cortical zone of the bone could be an alternative method for dating osseous remains.