Consistency and specificity in burglars who commit prolific residential burglary: Testing the core assumptions underpinning behavioural crime linkage

PURPOSE: Behavioural crime linkage is underpinned by two assumptions: (a) that offenders exhibit some degree of consistency in the way they commit offences (their modus operandi [MO]); and, (b) that offenders can be differentiated on the basis of their offence behaviour. The majority of existing studies sample at most three crimes from an offender's series of detected crimes and do not examine whether patterns differ across offenders. Here, we examine patterns observed across the entire detected series of each sampled offender, and assess how homogeneous patterns are across offenders. METHODS: Using a non-parametric resampling approach, we analyse the entire crime series of 153 prolific burglars to determine if they exhibit consistency and specificity in the way they commit offences. RESULTS: Findings suggest that offenders exhibit consistency in the way they commit offences. With respect to specificity, our results suggest that patterns are not homogeneous across offenders or the type of MO considered - some offenders exhibit more specificity than do others, and offenders are more distinctive for some aspects of their MO (particularly spatial choices) than they are for others. CONCLUSIONS: The findings provide support for the underlying principles of crime linkage, but suggest that some aspects of an offender's MO either conform to a common preference, or are perhaps more influenced by situational factors than stable scripted preferences. That some offenders fail to demonstrate sufficient specificity for accurate linkage suggests that identifying which crimes are likely to be the work of offenders who display more specificity a priori constitutes one challenge for future research of this kind.