Complex Criminal Investigations: Pitfalls and Opportunities in Police Investigative Practice

Investigating a crime involves an examination of several factors, including the type of crime committed and its specific features, as well as the characteristics of the suspects, witnesses and victims involved. These factors guide fact-finding and evidence gathering from law enforcement officers. Some variables can further increase the complexity of the investigative task and the need for specialised skills. In particular, multiple rather than single perpetrator crime, repeated compared to isolated incidents, violent and sexual crimes against vulnerable adult victims and children, communication barriers and lack of cooperation from the interviewees represent added complexities in an investigation. Psychological science has contributed to the recent development and advancement of investigative practice in some of these critical aspects of criminal investigations. However, some additional demands that increase the complexity of an investigation have not received sufficient scrutiny from both researchers and practitioners. To address this shortcoming, our research evaluates the effects of diverse understudied factors on current investigative practice, using field and experimental data. We gathered first-hand knowledge about investigative practice in diverse forces or services that provide a rich and unique insight into different procedures and processes involved in complex criminal investigations across different countries around the world (e.g., North-America, Europe, and Asia), which we complemented with empirical research with practitioners and lay people. Our aims were to analyse and evaluate current international investigative practice, inform future and novel research, and contribute towards effective evidence-based investigative practice. We researched how police investigators perform identification procedures in crimes involving multiple perpetrators. We also examined how current interviewing practice aims at securing cooperation and increasing disclosure. In particular, we inquired about the interviewing strategies and contextual manipulations practitioners frequently use and believe to be effective to elicit accurate and complete statements from witness and suspects. In addition, we explored how investigative interviews are conducted when interpreters are needed to communicate with victims and the impact of violence and emotionality in the accuracy of the interpretations. Lastly, we investigated which factors influence how practitioners and lay people assess the reliability and credibility of witnesses and victims, in cases concerning child sexual abuse allegations, and in investigations of isolated and recurring incidents. In this symposium, we will discuss the implications of our research findings and opportunities to improve investigative practice. Our analysis will focus on the identified pitfalls and perils of certain practices with respect to effective evidence gathering and upholding legal, ethical and human-rights standards. In addition, we will highlight aspects and potential solutions to the intrinsic challenges of these investigations that require further research, and offer recommendations for practitioners based on existing best-practice guidance when available. To conclude, we will discuss the importance and challenges of collaborations between researchers and practitioners.This symposium includes the submission of the following abstracts to the annual meeting of the European Association of Psychology and Law, Santiago de Compostela, Spain: - Tupper, N., Sauerland, M., Sauer, J., & Hope, L. (2019). Multiple Perpetrator Identification Practices: A Survey of Identification Administrators. - De La Fuente Vilar, A., Horselenberg, R., Landström, S., Strömwall, L. A., & van Koppen, P. J. (2019). Gaining Cooperation from Witnesses: An International Survey of Investigative Interviewers.- Hoogesteyn, K., Meijer, E. H., Vrij, A. (2019). A Look at Police’s Use of Context Manipulation Techniques for Suspect Interviews.- Wilson, L. (2019). Interpreting Violence: Concerns for Interpreter Emotional Bias in Investigative Interviews. - Sumampouw, N. E. J., Otgaar, H., & de Ruiter, C. (2019). The Influence of Extra Information About Child Sexual Abuse Alleged Victim to Police Perceived Credibility and the Interview Plan- Kontogianni, F., Hope, L., Taylor, P. J., Vrij, A., Gabbert, F. (2019). Reliability and Credibility Judgements of Witness Reports: Single versus Repeated Events.Key words: Criminal investigations, evidence-based policing, evidence gathering, information elicitation, credibility assessment.