Modelling crime linkage with Bayesian networks

 

When two or more crimes show specific similarities, such as a very distinct modus operandi, the probability that they were committed by the same offender becomes of interest. This probability depends on the degree of similarity and distinctiveness. A new paper:

de Zoete, J, Sjerps, M, Lagnado,D,  Fenton, N.E. (2015), "Modelling crime linkage with Bayesian Networks" Law, Science & Justice, 55(3), 209-217.
http://doi:10.1016/j.scijus.2014.11.005 

shows how Bayesian networks  can be used to model different evidential structures that can occur when linking crimes, and how they help in understanding how evidence that is obtained in one case can be used in another and vice versa. The flip side of this is that the intuitive decision to "unlink" a case in which exculpatory evidence is obtained leads to serious overestimation of the strength of the remaining cases.

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