Entomotoxicology examines how chemical substances affect different insect species that colonize decomposing organic matter and plays an important role when interpreting entomological evidence in forensic investigations. Flunitrazepam is a benzodiazepine with strong sedative effects that may influence insect development and physiology. Research investigating microbial community differences among necrophagous insect species exposed to various drugs remains limited. This study aimed to further examine the effects of flunitrazepam exposure on the development and microbiome composition of Calliphora vomitoria. For this, Calliphora vomitoria specimens were reared under controlled laboratory conditions and randomly assigned to control, low concentration (8 mg flunitrazepam), and high concentration (16 mg flunitrazepam) treatment groups. Specimens were weighed throughout development, and total genomic DNA was extracted from the collected developmental stages. Insect-specific bacterial targets are being evaluated using quantitative polymerase chain reaction (qPCR) to further characterize changes in the microbiome associated with flunitrazepam exposure. Preliminary results indicated that flunitrazepam exposure influenced body weight, particularly during larval development. Specimens exposed to the highest concentration exhibited reduced weights during the first and second instars, while no significant differences were observed during later developmental stages. No major differences in developmental duration were observed among treatment groups. Genomic DNA was successfully extracted from adult and first-instar specimens, yielding high DNA concentrations and purity. These preliminary findings highlight the importance of considering drug exposure when interpreting forensic entomological evidence.