In order to investigate the possibility of detecting host DNA isolated from larval crops and the effect of time elapse during digestion, the present study was carried out. Domestic pig cadaver was used as a case study model instead of real human corpse tissue by collecting of 3^rd instar larvae post-feeding and starving during24, 48, 72, and 96 hours. The identification of DNA extracted from pig tissues and from Sarcophaga carnaria Linnaeus and Chrysomya albiceps Wiedemann larval crops fed on deceased pig remains were carried out using PCR. The detection of DNA bands in the larvae of the two dipteran species was carried out by using Gel electrophoresis.  Results showed that the extracted DNA from larval crops of the two fly species was identical to that extracted directly from domestic pig decaying tissues. In addition, the PCR specifically amplified the domestic pig mtDNA cyt b gene with 203 bp amplicons. Results also showed that DNA could be clearly detected within approximately 72h after the removal of larvae from pig corpse, suggesting reliable consecration of insects as valuable evidence in crime scenes. These results are useful for further consideration of the estimation of postmortem intervals (PMI) by the aid of forensic entomology.