An examination of explicit and tacit knowledge in the decision making of Senior Investigating Officers in stranger homicide

Within the career of a homicide detective, the investigation of a stranger murder, where there is no known previous relationship between the perpetrator and victim, is a low frequency occurrence. While such crimes are rare, when they occur, they typically engender an inordinate public and media interest. It is against this backdrop that the Senior Investigating Officer (SIO) must lead, what is typically, a complex investigation and make crucial investigative decisions in the search for a perpetrator. In an attempt to investigate the domains of knowledge underlying SIO decision making in this complex problem-solving task, this thesis explores the explicit and tacit influences on their training and performance as SIOs in the context of stranger murder investigation. Specifically, the study sought to establish 1) whether there is a particular type of decision model that equates to how SIOs decide; 2) what evidence there is for a craft style of decision-making in the decisions of an SIO; 3) how is both tacit and explicit knowledge utilised within the decision-making of the SIO and 4) whether SIOs use hypothesis generation and hypotheses testing to avoid bias in their decisions. In order to explore these areas of enquiry, a qualitative research design was employed encapsulating three phases of data collection. The first phase was observation of the four-week National SIO course held at the Police College, Ryton. The second phase involved in-depth interviews with 11 SIOs from various forces in England and Wales focusing on their decision-making in a case of stranger murder that they had investigated. The third phase involved the content analysis of the same SIOs decision-logs for the murder that they focused on in the interview phase. Observation of the SIO training course amplified the enormity of the pressure that the SIO has to absorb during a ‘stranger murder’. As well as too much information, partial or even incorrect information exacerbates those pressures. It was noticeable that when dealing with a situation with which they were unfamiliar the SIOs adopted a ‘routinised’ approach to their investigative decision-making. It also became clear that the majority of SIO decisions are taken within the first 24-72 hours of an investigation. The decisions then begin to decline as the investigation progresses. The initial surge in decision making at the commencement of an investigation and then the rapid fall off and decline in decisions, although occurring in a simulated environment appeared to mirror what occurs in real world investigations. Thematic analysis of the eleven SIO interviews revealed four supra ordinate decision-making themes: 1) the course of an investigation, 2) mission, 3) knowledge work and 4) human factors. The course of an investigation theme was made up of five decision-making stages from the initial decisions regarding whether a murder had occurred, to organizing the response, identifying an offender, engagement with the crown prosecution service and finally post-charge decision-making. In the second theme, the pressures and problems encountered by SIOs in ‘doing the job’ of investigating a stranger murder are explored. The reality is that SIOs have human weaknesses and these frailties are exposed by the nature of the duty they undertake. The SIOs reflected on how they perceive their experience as murder investigators and the difficulties presented by that task. This included their interaction with others both within and outside the organisational structure and the balance of power that exists between these competing factions. Permeating this is the culture of the detective, a sense of mission, stoicism in the face of difficulty, and commitment to that undertaking which underpinned their attitudes and behaviour. In the third theme, SIOs commonly referred to the National Decision Model as the basis upon which they made their decisions. The final theme concerned what the SIOs said about themselves as investigators and solvers of murder. In this context, it included their views on the value of experience and the personal qualities they believed underpin a successful SIO. Overall, the findings reveal that, as few SIOs have investigated a stranger murder, they draw on their accumulated investigative experience, dealing with the familiar type of murder. Their values and beliefs as to both how and who committed the murder influence the decisions they take