Case linkage uses crime scene behaviours to identify series of crimes committed by the same offender. The research presented here tests the underlying assumptions of case linkage (behavioural consistency and behavioural distinctiveness) by comparing the behavioural similarity of linked pairs of offences (i.e. two offences committed by the same offender) and unlinked pairs of offences (i.e. two offences committed by different offenders). It was hypothesised that linked pairs would be more behaviourally similar than unlinked pairs thereby providing evidence for these two assumptions. Logistic regression and receiver operating characteristic analyses were used to explore which behaviours can be used to reliably link personal robbery offences using samples provided by two police forces (one urban and one rural). The method of generating unlinked pairs was then refined to reflect how the police work at a local level, and the success of predictive factors re-tested. This research provided evidence supporting the assumptions with linked pairs displaying more similarity than unlinked pairs across a range of behavioural domains. Inter- Crime Distance and Target Selection emerged as the most useful linkage factors with promising results also found for Temporal Proximity and Control. No evidence was found to indicate that either the Approach used or the Property stolen were useful for linkage. The addition of extra behaviours into domains improved performance in some instances but not substantially. The potential impact of group offending on the assumptions was also tested. Although there were some differences found between group and lone robberies, the research demonstrated that case linkage remains feasible provided that the offences under examination are either group or lone in nature rather than a mixture of the two. A supplementary study gathering the views and experiences of police crime analysts regarding case linkage helped put these new quantitative findings into operational context.

Text in Afrikaans / In die ondersoek na die modus operandi van die bankrower: 'n kriminologiese introspeksie, kan die ondergemelde drie dimensies onderskei word: Die eerste dimensie is 'n kriminologiese introspeksie wat die betekenis wat bankrowers self aan die uitvoer van bankrooftogte heg, behels. Hierdie leefwereld van die subjekte word deur die navorser "betree" en mede-verken. Doelgerigtheid, morele oorwegings, teesin in geweld, charisma, kognitiewe vermoens en 'n materialistiese ingesteldheid is begrippe wat die bankrower as mens belig. Die tweede dimensie word verteenwoordig deur die begrondingsteorie as navorsingsmetode, gebaseer op die werk van Strauss en Corbin {1990), wat toegepas word ten einde sodanige navorsingsdoelstelling te fasiliteer. Tydens die aanvanklike fase van die ondersoek is daar met 28 bankrowers in aanhoud i ng, gefokusde semi -gest ruktureerde ind i epte-onderhoude gevoer. Opvolgonderhoude is met ses van die 28 subjekte gevoer, met die doel om 'n substantiewe begrondingsteorie te ontplooi, verskille op te klaar en die geldigheid van die data te verhoog. Die derde dimensie reflekteer vervolgens die ontplooiing van 'n substantiewe begrondingsteorie wat weerspieel word in proposisies en wat in vier fases van die modus operandi van die bankrower onderskei word, naamlik die beplanning-; uitvoering-; afhandeling-; en heroorwegingsfase. Elk van die ge'identifiseerde fases word gekenmerk deur progressiewe beweging, natuurlike kontinu'iteit, emosionele belewenisse en 'n individualistiese inslag. Twee kernelemente, naamlik besluitneming en rasionaliteit staan prominent binne die kader van die modus operandi van die bankrower. Die substantiewe begrondingsteorie is daarop ingestel om die verskynsel wat bestudeer word, te verklaar. Seide die oorweging van die ondersoek asook ander doelstellings van die navorser word binne die teorie geakkommodeer. Verdere vergelykende studies kan daartoe bydra om die substantiewe begrondingsteorie te verfyn, te falsifiseer, 6f by gebrek daaraan, tot 'n formele teorie uit te bou. Derhalwe word die begrondingsteorie as navorsingsmetode nie slegs as toepaslik beskou vir toekomstige navorsing oor onderwerpe waaroor daar 'n gebrek aan empiriese bevindinge bestaan en waaroor relatief min kennis in kriminologiese literatuur voorkom nie, maar hou dit ook die voordeel van 'n pluriforme navorsingstudie in. / In the investigation into the modus operandi of the bank robber: a criminological introspection, three dimensions can be distinguished. The first dimension is a criminological introspection comprising the meaning attached by bank rob.bers to the execution of bank robberies. This world of the subjects is entered and co-scouted. Sense of purpose, mora 1 considerations, aversion to violence, charisma, cognitive powers and a materialistic disposition are conceptions that elucidate the bank robber as a human. The second dimension is represented by the grounded theory as research method, based on the work of Strauss and Corbin (1990), which are applied to facilitate such research aims. During the initial phase of the investigation, focused, semi-structured, in-depth interviews were held with 28 bank robbers in detention. Subsequent interviews were held with six of the 28 subjects, aimed at expanding a substantive grounded theory, to clear up differences and to increase the validity of the data. The third dimension reflects the development of a substantive grounded theory which is revealed in propositions and signalised in four phases of the bank robber's modus operandi, namely the planning, execution, disposal and reconsideration phases. Each of these identified phases is characterised by progressive movement, natura 1 continuity, emot i ona 1 experiences and an individualistic infusion. The basic elements, namely decision-making and rationalisation, are prominent in the cadre of the bank robber's modus operandi. The substantive grounded theory is aimed at explaining the study phenomenon. Consideration of the investigation as well as other aims of the researcher are accommodated in the theory. Further comparative studies can assist in refining or falsifying the substantive grounded theory or, failing, to expand it to a formal theory. The grounded theory is therefore regarded as appropriate for future research on subjects about which there is a lack of empirical findings and relatively little knowledge in criminological literature. The theory offers, in addition, the advantage of a pluriform research study. / Sociology / D. Litt et Phil. (Kriminologie)

Text in Afrikaans / In die ondersoek na die modus operandi van die bankrower: 'n kriminologiese introspeksie, kan die ondergemelde drie dimensies onderskei word: Die eerste dimensie is 'n kriminologiese introspeksie wat die betekenis wat bankrowers self aan die uitvoer van bankrooftogte heg, behels. Hierdie leefwereld van die subjekte word deur die navorser "betree" en mede-verken. Doelgerigtheid, morele oorwegings, teesin in geweld, charisma, kognitiewe vermoens en 'n materialistiese ingesteldheid is begrippe wat die bankrower as mens belig. Die tweede dimensie word verteenwoordig deur die begrondingsteorie as navorsingsmetode, gebaseer op die werk van Strauss en Corbin {1990), wat toegepas word ten einde sodanige navorsingsdoelstelling te fasiliteer. Tydens die aanvanklike fase van die ondersoek is daar met 28 bankrowers in aanhoud i ng, gefokusde semi -gest ruktureerde ind i epte-onderhoude gevoer. Opvolgonderhoude is met ses van die 28 subjekte gevoer, met die doel om 'n substantiewe begrondingsteorie te ontplooi, verskille op te klaar en die geldigheid van die data te verhoog. Die derde dimensie reflekteer vervolgens die ontplooiing van 'n substantiewe begrondingsteorie wat weerspieel word in proposisies en wat in vier fases van die modus operandi van die bankrower onderskei word, naamlik die beplanning-; uitvoering-; afhandeling-; en heroorwegingsfase. Elk van die ge'identifiseerde fases word gekenmerk deur progressiewe beweging, natuurlike kontinu'iteit, emosionele belewenisse en 'n individualistiese inslag. Twee kernelemente, naamlik besluitneming en rasionaliteit staan prominent binne die kader van die modus operandi van die bankrower. Die substantiewe begrondingsteorie is daarop ingestel om die verskynsel wat bestudeer word, te verklaar. Seide die oorweging van die ondersoek asook ander doelstellings van die navorser word binne die teorie geakkommodeer. Verdere vergelykende studies kan daartoe bydra om die substantiewe begrondingsteorie te verfyn, te falsifiseer, 6f by gebrek daaraan, tot 'n formele teorie uit te bou. Derhalwe word die begrondingsteorie as navorsingsmetode nie slegs as toepaslik beskou vir toekomstige navorsing oor onderwerpe waaroor daar 'n gebrek aan empiriese bevindinge bestaan en waaroor relatief min kennis in kriminologiese literatuur voorkom nie, maar hou dit ook die voordeel van 'n pluriforme navorsingstudie in. / In the investigation into the modus operandi of the bank robber: a criminological introspection, three dimensions can be distinguished. The first dimension is a criminological introspection comprising the meaning attached by bank rob.bers to the execution of bank robberies. This world of the subjects is entered and co-scouted. Sense of purpose, mora 1 considerations, aversion to violence, charisma, cognitive powers and a materialistic disposition are conceptions that elucidate the bank robber as a human. The second dimension is represented by the grounded theory as research method, based on the work of Strauss and Corbin (1990), which are applied to facilitate such research aims. During the initial phase of the investigation, focused, semi-structured, in-depth interviews were held with 28 bank robbers in detention. Subsequent interviews were held with six of the 28 subjects, aimed at expanding a substantive grounded theory, to clear up differences and to increase the validity of the data. The third dimension reflects the development of a substantive grounded theory which is revealed in propositions and signalised in four phases of the bank robber's modus operandi, namely the planning, execution, disposal and reconsideration phases. Each of these identified phases is characterised by progressive movement, natura 1 continuity, emot i ona 1 experiences and an individualistic infusion. The basic elements, namely decision-making and rationalisation, are prominent in the cadre of the bank robber's modus operandi. The substantive grounded theory is aimed at explaining the study phenomenon. Consideration of the investigation as well as other aims of the researcher are accommodated in the theory. Further comparative studies can assist in refining or falsifying the substantive grounded theory or, failing, to expand it to a formal theory. The grounded theory is therefore regarded as appropriate for future research on subjects about which there is a lack of empirical findings and relatively little knowledge in criminological literature. The theory offers, in addition, the advantage of a pluriform research study. / Sociology / D. Litt et Phil. (Kriminologie)