Medico legal forensic entomology is the science and study of cadaveric arthropods related to criminal investigations (Catts and Goff 1992). The study of beetles is particularly important in forensic cases. This can be helpful in determining the time since death or post-mortem interval (PMI) and also obtain qualitative information about the location of the crime (Matuszewski et al. 2008; Byrd and Castner 2009). Insects attracted to the chemical cues emitted by a dead body. They have a specific faunal succession to attack a decomposing body or exuded biological fluids‚ as carrion beetles are usually found in the late stages of body decomposition (Byrd and Castner 2009). Two major groups of insects are predictably attracted to remains and provide useful evidence in forensic investigation; the flies and the beetles (Catts and Goff 1992).
A variety of beetle species are necrophilous, or specifically attracted to carrion while not feeding on the carrion itself (Mashaly 2017; Rivers and Dahlem 2013).
The order Coleoptera comprises a number of forensically important families, viz. Staphylinidae, Nitidulidae, Scarabaeidae, Silphidae, Dermestidae, and Histeridae (Byrd and Castner 2009; Rivers and Dahlem 2013). Histeridae is a family of beetles commonly known as Clown beetles or Hister beetles (Catts and Goff 1992). Clown beetles are usually small, seldom getting beyond 10 mm in length. Both the larvae and adults are predacious and feed readily on juicy maggots and fly puparia (Byrd and Castner 2009). Histeridae are a large family with more than 3,502 identified species. They are frequent in tropical and subtropical climates. Their important diagnostic characters include geniculate and capitate antennae that are folded into a pronotal groove at repose (Bald 1935).
The legs are short and retracted, the fore tibia is fossorial, and the middle tibia frequently has long spines. The males have a hyaline membrane between the claws of fore tarsi. The abdomen has 5 visible sternites. Elytra do not cover the entire abdomen so that the apical two tergites are visible from above. Elytra are usually striate and punctuate (Geden and Axtell 1988).
The Histeridae family are predators that inhabit animal dung and carrion where they feed on other insects (Daria et al. 2011). Adults and immatures of Histeridae are found in association with decaying animal or vegetable matter, which suggested that they were principally scavengers. But it is becoming generally recognized that many species are predaceous on various insects (Ohara 2003).
Because the Histeridae family can be found on carrion, they have proven to be important in certain forensic investigations (Ozdemir and Osman 2009). The predacious Hister beetles will feed on the various insects on the body, primarily Diptera. To estimate a person’s time of death, forensic investigators must look at the insects on the body and determine the time of colonization (Kulshrestha and Satpathy 2001). If the Histeridae beetles are present, the investigator can assume that some of the other insects have been eaten by the Hister beetles.