Homicide cases where the victim’s remains are hidden are particularly harmful to the victim’s families and the community. For investigators, these cases can also be particularly complex. They not only have to solve the case, they also have to coordinate a search for the victim and manage the victim’s family and community expectations for timely justice.When multiple people work together to hide a body, things get even more difficult for investigators, and little research has been done to study the group dynamics of people who work together in these situations.My recently published research examining 36 cases of group-based body disposal in Australia between 1988 and 2020 has found unique hiding behaviours not previously identified.What we know about group body disposalOften, police rely on historical information regarding hiding patterns – such as offenders hiding remains in bushland, or in lakes and waterways – in addition to detailed information collected through investigations to narrow down search areas.However, research examining body disposal patterns is largely drawn from cases involving a single perpetrator.Group-based body disposal is when multiple offenders (two or more) are involved in hiding the victim’s remains. Having multiple offenders involved can alter the way in which remains are hidden.There are many factors in group decision-making that differ from individual decision-making. For example, hierarchies exist in groups where a dominant leader may control the decision-making process.Groups may contain various levels of experience or expertise that one person may not have.And more resources may be available in groups, such as the ability to shift more weight or access to equipment such as vehicles.For investigators searching for remains, this may make the task of unpacking timelines and identifying possible search locations more complex. The dynamics found in groups and the options available to them increase the complexity of decision-making and, in turn, the possibilities for disposing of remains.What my research foundTemporary storage sites are sometimes used by offenders to store victim remains after removing them from the murder scene and before placing them at the final disposal site. Offenders use a range of locations to store and dispose of remains. A temporary storage site could be anything from a tract of bushland to a warehouse. Final disposal sites vary based on their remoteness but the most likely choice for offenders is bushland. Evidence shows remains are stored for an average of 52 hours before being moved to the victim’s final resting place.Why did offenders use temporary storage sites?The purpose of temporary storage sites vary. Offenders may wish to move remains from the murder scene quickly to reduce the risk of detection or to gain time to develop a rational disposal plan.In two cases in my study, remains were moved to a temporary site for the purpose of “treating” remains for disposal. Treating is the term used for actions such as dismemberment, burning, chemical degradation or other methods of breaking down remains.These remains were then moved to a final disposal site.The ability to treat remains is more likely to be possible in a group with access to more resources.The reason for treating remains may vary. Often it is simply a method of disguising the victim’s remains or making transportation of remains more practical.However, these additional sites and the resources required to treat remains may offer more opportunity for investigators to detect and gather evidence. One crime scene may become three: a murder scene, a temporary storage site and permanent disposal site.How this may help investigatorsWhile the factors in successfully detecting a victim’s remains are complex, it is possible the offenders’ extra attempts to treat and conceal remains may increase the likelihood of detection, at least in the long term. While most victims’ remains in my study were detected quickly (within 30 days), some of the untreated remains went undetected for far longer (600+ days).All in all, research into group-based body disposal provides police with more information to assist in their investigations.Identifying unique behaviours may assist police in delivering justice for victims’ families and communities and reducing the grief caused by prolonged searches.Nathan Ryan is the recipient of an Office of National Intelligence National Intelligence Postdoctoral Grant (project number NIPG-2023-008) funded by the Australian government.