One of the most common methods of maternal filicide is by fire. In this case study, a 40-year-old female and her children were found completely burned in a burnt out car. All bodies showed a degree of destruction by fire consisting to a level 3 of the Crow-Glassman Scale (CGS) and early stage of insect activity. Toxicological analyses were performed on soft tissues and body fluids still available. The results were positive for diazepam and its metabolites only for children with blood concentrations consistent with therapeutic doses of benzodiazepines. Home video surveillance cameras confirmed sedation prior to death recording the mother while administering some drops of sedative drugs in a soft drink to the children just a couple of hours before setting fire to the car. Based on autopsy findings, all victims were still alive at the time of fire. The cause of death was determined as carbon monoxide poisoning and fatal thermal injuries by fire. This case study has a special focus on the entomotoxicology and the potential role of insects in death investigations of burnt bodies, supposed to be an inadequate substratum for insect colonization. It demonstrates that in burnt bodies, arthropod colonization can be quite immediate after fire is extinguished. Toxicological analyses performed on larvae actively feeding on the children’s bodies were positive for diazepam and its metabolites in small amount compared with blood concentrations, whereas the larvae collected from the mother’s body were totally negative. These data, according to the autopsy findings and the toxicological results from the victim’s blood and tissues, supported the suspect of a non-lethal sedation prior to death, which is a common behaviour in maternal filicide.