Linkage Analysis as Evidence in Court: A Thematic Analysis of Mock Juror Deliberations

Abstract

Linkage analysis has, albeit occasionally, been presented in courts across the world as evidence that a series of offences possess behavioural similarities and distinctiveness from other offences, meaning they have probably been committed by the same individual. It is therefore imperative to ascertain how linkage analysis is regarded by juries within the context of deliberations. Three groups of participants (N = 22) eligible for jury duty in England and Wales viewed a simulated rape and murder trial derived from an actual South African case. Linkage analysis formed the sole evidence against the defendant in the two later offences, although DNA matches and eyewitness identifications of the defendant were present in the two earlier offences. Participant deliberations were recorded and subjected to thematic analysis. Five themes were discovered: behavioural consistencies and inconsistencies, physical versus case linkage evidence, barriers to admissibility, potential uses of linkage analysis, and dependence of lay knowledge. Jurors' over-reliance on erroneous lay knowledge contributed to their conclusion that linkage analysis is, at present, unrepresentative evidence that cannot independently indicate a defendant's culpability. However, participants believed that linkage analysis could be a useful tool within investigations and, with further research evidence, in court in England and Wales.

The practice of crime linkage: A review of the literature

“…All articles were assessed for relevance; only publications where the practice of crime linkage was the main focus were included in this review. The following sorts of documents were not included in the review: the use of crime linkage in court, such as studies of the reception of crime linkage evidence by juries (e.g., Charron & Woodhams, ; Fawcett & Clark, ); investigations of the justification of claims made about links by practitioners (Almond, Alison, & Porter, ); and descriptions of how the assumptions of crime linkage might be considered by an analyst when conducting linkage and how these assumptions would need to be considered in terms of the benefits and risks of crime linkage (Alison, Goodwill, & Alison, ). The reliability of linkage is also questioned in some literature including, as noted above, its lack of acceptability as legal evidence given its failure to meet the Daubert criteria for admissible expert evidence (Ormerod & Sturman, ), but as noted above, this was not considered the primary purpose of this review.…”

Evaluating evidence in linked crimes with multiple offenders

“…Labuschagne [13] states that linkage analysis is especially important when there is evidence that suggest culpability for some, but not all offenses. However, in Fawcett and Clark [14], the authors note that the linkage analysis is, at present, unrepresentative evidence that cannot independently indicate a defendant's culpability. In other words, linkage analysis 'alone' is insufficient evidence.…”