Effects of Heat Exposure Duration on Saliva Traces on Cigarette butts as Forensic Identification Tools

摘要

Identification processes are not only conducted on the dead bodies of criminal victims, but also on the evidence found at the location. The length of time between the crimes happening and the investigation of the evidence is a problem in relation to the blood group identification process through saliva traces on cigarette butts. Wet saliva usually becomes trace in an hour and 40 minutes at room temperature, and up to less than 3 hours if there any influencing factors. The purpose of this research is to analyse the effects of heat exposure duration on the protein content of the saliva traces on cigarette butts in order to help the forensic blood group identification process. A time series design was used in this research in which 18 cigarette butts were collected from 6 individuals of blood groups A, B, and AB. The samples were then incubated for 1.3 and 6 hours respectively. The protein content was determined using a trizol reagent and Spectrophotometer UV. Statistical analysis using a T-test was conducted to analyse the results. There was a decrease in the protein content of the saliva trace samples at the time points of 1, 3 and 6 hours. The protein content of the saliva could still be detected at the time points of 1, 3 and 6 hours. These findings suggest that the protein analysis of saliva trace samples on cigarette butts can be used in the forensic blood group identification process.