The commonest history gotten from relatives was that of sudden traumatic death followed by burial and bodies found floating on the water that were retrieved and buried by the river bank, before the coroner’s mandate for EPME.
Most cases were financed by the relatives of the deceased and due to financial constraints, 91.5% of the PME were performed by the grave sides. Only the study by Sprogoe-Jakobsen et al. (2001) in Kosovo made mention of PME venue, in which the PME were not done in autopsy suites, but on different types of surfaces (including plastic apron on the ground, horse-carts, picnic tables, and wooden tables) and non-availability of water. Though cheaper for the financers, PME by the grave side were more tedious because they are not proper autopsy settings and usually posed more challenges for the pathologist and his assistants. A fact agreed by Sprogoe-Jakobsen et al. (2001). We do not rule out the fact that some (though few) facts may have been missed. Its major advantage is that for all cases, the pathologist was present and conducted/supervised the exhumation (thereby protecting against wrong exhumation technique since our assistants in this part of the world do not have formal education, training, or exposure for such a procedure). The pathologist is the contact person for the investigating agency and only his/her report is honored. In Quebec, Canada, in 37.5% of situations, the pathologist was not at the scene of the exhumation (Kremer and Sauvageau 2008).
Normally mass graves are rarely used except in mass disasters. Even in such situations, the bodies are first placed in separate well-tagged body bags, buried in trenches, parallel to each other and never stacked together in an overcrowded grave (Cordner et al. 2016). In such situations, these mass graves are properly marked above the ground and tracked for future reference and identification of remains when the logistics are available. Of the 2 mass graves seen in the index study, their bodies were not put in separate body bags, they were not buried in trenches (bodies were kept on top of each other) nor were the graves marked or tracked. For the mass grave containing 8 bodies, they were almost completely decomposed; however, the skulls showed evidence of traumatic skull fracture and an eye witness (a surviving family member) confirmed the number of people that were buried. Normal burial areas depending on culture and religion in our setting include the following: deceased compound/house, farmlands, and cemeteries. Riverbank is not an ideal burial area, but in the index study, it was seen in 23.4% of cases (n = 11). A mass grave containing 11 bodies was situated by the riverbank, because these unidentified bodies were seen floating on the river and locals/users of the river wanted to avoid polluting their source of water, retrieved the bodies and buried them by the riverbank. The recovery and removal of the bodies from the riverbank helped to prevent the imagined water pollution. Hence, the EPME helped to save the community. Eight cases in the index study were buried in the forest, uncompleted house, and disused pit. These were kidnap and cultism-related deaths. This confirms the known fact that exhumations carried out at remote places are usually secret disposals, and the outcome will be violent death of homicidal intention. This contrasts exhumations in notified areas (regular graveyards) where the outcome are either suicide or accident or natural death (Saukko and Knight 2004).
An ideal grave should have a depth of 180 cm (1.8 m). But in recent times, a depth of 129.54 cm is accepted, such that coffin takes 38.1 cm and 90 cm is left above the coffin, to contain sand (Wikipedia 2018). The ideal grave should be free from water or hard rock. There was significant correlation (P = 0.025) between grave adequacy and the history summary. The presence of 2 not properly arranged mass graves contributed significantly (since it accounted for more than 40% of cases (n = 19). Most of the graves in the index study were inadequate. This could be closely tied to the summary of history of individual cases. Majority were hurriedly done, either to prevent a suspected pollution, to cover a kidnapped case gone sour, or due to a sudden traumatic death. The reasons above also explain why a casket was rarely used, despite the fact that these EPME were done in areas where it is cultural habit to bury with a casket. This finding also collaborates with that of Ammani et al. (2016) that opined that shallow graves (depths of 30 to 60 cm) usually indicated hurried disposal in secrecy by perpetrators so as to conceal a crime.
A correlation of the grave condition (mainly subjective assessment of the soil covering the grave) and the condition of the body on exhumation was not significant (P = 0.086). Hence, the standard way (forensic archeology) remains the best option.
Most of these EPME were done in parts of the country where dead bodies are usually preserved by formalin embalmment before burial. However, a significant observation in this study is that in most cases (78.7%, n = 37), no form of preservation was done. This observation may not be unconnected with the history surrounding the deaths. Except for skeletonized bodies in mass graves, identification is not usually a major problem in EPME, because in many occasions, the complainants/relatives are usually sure of the grave sites except in kidnap cases. When in doubt of identification, DNA profiling of the long bones and teeth have given excellent results, though identification was not an issue in the index study and none was done in our series (Ammani et al. 2016; Nouma et al. 2016).
All 47 cases except 1 were exhumed within 6 months of burial. This is similar to observations in previous studies in Quebec, Canada, and Munster, Germany, where most EPME were done within a year of burial (Kremer and Sauvageau 2008; Karger et al. 2004). In Kosovo, the interval was up to a year and 6 months (Sprogoe-Jakobsen et al. 2001). The likelihood of success of an EPME depends on the extent of morphological changes, post-mortem decay, and the object that caused the injury, including the part of the body injured. A lot of changes ranging from mechanical to chemical erosion due to the effects of soil and the action of predators and plants usually occur on the buried body (Saukko and Knight 2004). Despite these changes, a lot of information can be obtained even when the body has been buried for months or even years. A significant correlation (P = 0.018) was observed between the duration of the body in the ground and the condition of the body on exhumation. This is similar to findings by Bardale et al. 2012; Ammani et al. 2016; Asad et al. 2014; and Sprogoe-Jakobsen et al. 2001. The majority were either moderately to severely decomposed or were bony remains. The major disadvantage of delayed exhumation is the loss of significant information (especially soft tissue injuries) (Bardale et al. 2012; Kumar et al. 2011; Nouma et al. 2016). In moderate to advanced stages of decomposition, their marks of violence on the soft tissue are usually lost. Organs will also be in various stages of decomposition, such that tissue histopathology will be of little assistance (Agarwal et al. 2017). Loss of the soft tissue also hinders the proper interpretation of findings (Nouma et al. 2016). A major cause of delay in exhumation in our setting is the duration it takes before culprits/suspects in kidnap/cultism cases who usually give information about the location are found. Another major factor is the issue of financing. In Nigeria, most cases of EPME are financed by the relatives of the deceased. In Pakistan, the major reasons for delay in EPME are the fear of the living that the procedure is a dishonor to their late dear ones and due to lengthy legal procedures before an approval to do EPME is given (Asad et al. 2014). Many factors like the nature of terminal illness, season of burial, burial practice, presence of coffin or other protective means, nature and temperature of the soil, and the duration of post mortem interval determine the condition of the body on exhumation (Bardale et al. 2012; Saukko and Knight 2004). In Germany, the mostly low temperature helps in preserving the body, whereas in Pakistan, hot climate, water logging of graves, salinity, and improper drainage of graveyards quickens decomposition (Karger et al. 2004; Asad et al. 2014).
Based on the manner of death classification, all deaths could be accidental, homicidal, suicidal, natural, or undetermined (Hanzlick et al. 2002). EPME do not always provide the answer to the cause of death/manner of death in all circumstances. Many authors reported an undetermined/inconclusive EPME in their various works. The manner of death was undetermined in 36.2% of cases in this series, mainly due to advanced decomposition and no bony injury seen. Though, this does not rule out severe soft tissue injuries of any pathology or natural causes of death. The index rate of 36.2% is within the range of 15.5%, 33.4%, 33.5%, and 34.4% observed in Sindh, Pakistan; interior of Sindh, India; Nagpur, India; and Munster, Germany, respectively (Bardale et al. 2012; Karger et al. 2004; Kumar et al. 2011, Agarwal et al. 2017). However, due to the marked difference in sample size in the various studies, this linear generalization of undetermined cases may not holistically apply. The sample size in Germany was the highest (155 cases) and had a lower number of decomposed cases due to delayed putrefaction of corpse because of cold season in many months of year and application of sophisticated diagnostic techniques like immunocytochemistry (Karger et al. 2004). The rate of 36.2% is very significant; hence, some practitioners feel that exhumations are of little help in medicolegal investigations. A trained criminal might delay showing a burial site for long duration, with an aim to reveal it when he/she feels that a body “say strangulated or choked body might have decomposed enough. However, even negative EPME that reveals only bony remains without fracture or any bony lesion has answered a medicolegal question to an extent (Saukko and Knight 2004).
Homicidal deaths were most commonly seen, similar to previous studies (Bardale et al. 2012; Karger et al. 2004; Nnoli et al. 2013; Sprogøe-Jakobsen et al. 2001). Skull fracture was the most common pattern of homicide seen, distantly followed by gunshots. At times, the exact cause of death was not seen but associated death events like tying up was seen.
Toxicological investigations were done in 3 cases and were all negative. Due to the small number, no logical conclusion could be extrapolated from it. Duration of body in the grave may have contributed to no poison detection.
Limitations
Imaging studies were not routinely done, except for 2 cases of bony remains. The majority of the PME were by the graveside. Toxicology was done in only 3 cases, while immunohistochemistry was not done in any case. Anthropologist was not involved in any of the exhumations.