Samenvatting

Crime scene investigations require rapid decision-making under complex conditions, often without the opportunity for revision. Task-relevant information from similar cases can support Scene of Crime Officers (SoCOs) in making these decisions. Decision support can reduce human error and subjectivity, provide a sound basis for decision-making, and enhance transparency. What is not known is how and when to provide such decision support information so as to have the most improved outcomes. This study examines the influence of (1) providing information on the probability of recovering perpetrator DNA on decisions regarding the collection and triage of traces; (2) the timing of information provision (before trace collection, during trace collection, or during subsequent triage); and (3) differences between SoCOs and other professionals from the criminal justice system without crime scene experience. The results indicate that information on DNA success rates influences participants' decision-making. Informed participants sampled a higher proportion of locations with a high DNA success rate and sampled a lower proportion of locations with a low DNA success rate. Inconsistent with participant self-reporting, the results indicate that the impact of task-relevant information does not differ between the phases of the crime scene investigation. Lastly, this study indicates a significant difference between SoCOs and inexperienced participants for the collection of traces if participants had not received information but indicates no difference if participants had received information for either the collection or triage of traces. The results show tangible effects of providing task-relevant information, particularly when provided early in the process. However, care should be taken that SoCOs do not over-rely on such information, as case-specific circumstances must always be considered.