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The incidence of temporary storage sites was among the novel findings of a new Australian Catholic University study into group-based body disposal in murder cases.

ACU criminologist Nathan Ryan examined 36 cases of group-based body disposal in Australia between 1988 and 2020 and found unique hiding behaviors not previously identified.

The research, which will eventually contribute to police investigation methods in missing persons cases, showed timing was critical.

Dr Nathan Ryan, a Research Fellow at ACU's Thomas More Law School, found about half of concealed murder victims were discovered within 22 days. The average time from deposition to discovery was 289 days.

"The first week or two is critical. If nothing has been found in that window, then the odds of locating hidden remains grow longer by the day," Dr Ryan said.

Dr Ryan has been collaborating with the Australian Federal Police on developing a psychological profile that will ultimately help detectives investigate missing remains.

Published in the International Journal of Police Science & Management, the found some previously unstudied behaviors in the field of homicide, such as the presence of temporary storage sites for remains, and the use of multiple disposal sites for dismembered remains and other items relating to the murder.

The mean time from murder to disposal of the remains was 30 hours.

"That decision process would be of profound interest to investigators," Dr Ryan said. "I would expect that covering your tracks would be an urgent priority."

According to Dr Ryan's examination of data collected from legal documents such as sentencing reports and appeal documents, the shortest time to detection was one day and the longest 3315 days.

The largest proportion of perpetrators used burial as a means of concealment. However, 37.5% chose to place the victim's remains in the open without any coverage at all.

Contrary to previous research into group-based offending, the average age of both a primary offender and an accomplice is in their early 30s. In the specific case of homicide, this is an interesting finding, as group-based homicide tends to involve offenders who are young, in many cases, adolescents.