After World War I, the Dutch police, inspired by the German example, underwent a fast modernisation of its organisation. Two generations of police officers were the pacesetters in this reform. Technological innovations made them realize that the effectiveness of the police could be increased, that they had acquired the status of professionals, thanks to their new insights, and that professional thieves were their main enemies. During the 1930s, the police renewal stagnated, but the ties with Germany were not broken. Based on shared beliefs, some innovators rallied to the side of the German occupiers during World War II. In the end, the renewal movement did not recover from the experiences during the occupation.

Following the evaluation regarding the judicial error in the Schiedam park murder (‘Schiedammer parkmoord’), the Public Prosecutor, Police and the Netherlands Forensic Institute (NFI) have drawn up an enhancement program to prevent future errors. Part of this program is to fill 20% of the posts within the police investigation process with those who have completed a higher education study of ‘criminal investigation’ and have obtained the Master of Criminal Investigation (MCI) title. One of the MCI’s tasks is to act as counterparties within the investigation research, to reduce the tunnel vision that develops within these investigations. In this way, more attention can be paid to alternative scenarios, so that judicial errors are less likely to occur.

Current mapping of organized crime groups (OCG’s) serves two opposing needs simultaneously: firstly, researching OCG’s should be done as judiciously as possible, due to the consequential nature of ensuing police investigations. Secondly, police analysts experience severe constraints on their OCG-reports, because of the demand by police management for ‘objectified’ reports, describing crime groups as briefly as possible in terms which allow for comparison of groups. This drive towards streamlining OCG-mapping comes at a cost: not all groups fit into the prescribed formats. We need to re-think the way in which we map OCG’s so as to better support police investigations.

Various paradigms on the structures of organized crime have shaped the criminal investigational approach within the Dutch police towards criminal networks. The idea of pyramid-shaped mafia structures, as dominant in the 1970s, led to large-scale and long-term criminal investigations, trying to get to the ‘top’ of the network. In the 1990s, the image of separate criminal groups, working independently from each other, led to isolated criminal investigations on distinct criminal networks. Today, new insights that have arisen from scientific studies and police practices call again for a renewal of investigational strategies. As shown in this article, criminal networks are not limited by social, cultural or physical boundaries and show a rapid recovery after interventions by state actors. For these reasons, the efficiency of police practices depends on the extent to which the police is able to move along with these networks.

The Research Programme Police and Science was launched in 1999 with a mission to contribute towards the development of scientific knowledge with respect to the organisation and performance of the police and to promote the actual application of relevant new knowledge and understanding of police and safety practice. In this article we explore the challenging balance between those two worlds of researchers and practitioners. Scientific research can contribute to new methods or instruments in police forces and new training programmes. Based on former experience the conditions are defined that are necessary for a professional en productive relationship.

In many police investigations, a psychic turns up to help the investigation with his ‘extraordinary knowledge’ of the crime and the crime scene. Little is known about how the Dutch police deals with psychics and their information. We conducted research into this phenomenon through interviews with experts, a review of the legal literature and an online questionnaire for police practitioners. Although a guideline by the public prosecutor’s office states that psychics are not to be consulted without permission, most police practitioners are not aware of this guideline. At the moment, little is known about the actual use of information of psychics in police investigations.