An Investigation into the Presentation and Evaluation of Alibi Evidence in the Courtroom

McMillan, Katie (2025) An Investigation into the Presentation and Evaluation of Alibi Evidence in the Courtroom. Doctoral thesis (PhD), Manchester Metropolitan University.

Preview

Available under License Creative Commons Attribution Non-commercial No Derivatives. Download (4MB) | Preview

Abstract

An alibi, as a claim that the accused was elsewhere at the time an offence was allegedly committed, has the potential to be a defence worthy of vindication or (potentially, erroneous) conviction. Alibis are a leading contributory factor in cases of miscarriages of justice, yet research remains nascent. To ensure an effective, fair, and equitable legal system, thereby mitigating for wrongful convictions, it is vital that research seeks to redress this paucity. The thesis provides an integrative, mixed methodological investigation into the courtroom presentation and evaluation of alibis, achieved through three distinct, yet interconnected, studies. In Study One, four criminal barristers took part in semi-structured interviews to explore their perceptions, experiences, and approaches to questioning of alibis in court: the first of its kind within the jurisdictional context of England and Wales. The findings demonstrated that barristers were professionally sceptical and distrustful of such evidence. Direct examination seeks to present the defence using a controlled, story narrative, whilst cross-examination undermines and discredits the alibi by exploiting testimonial (between-statement) inconsistencies and discrediting the defendant and/or alibi witnesses manner, demeanour, or character. Informed by the real-world cross-examination techniques identified in Study One, 204 jury-eligible participants took part in Study Two, whereby the effect of alibi between-statement inconsistencies and prior conviction evidence on mock juror evaluations and decision-making was examined. Such factors had a significant negative effect on the verdict and appraisals made by mock jurors, demonstrating such techniques are indeed effective in undermining and discrediting the defence when evaluated by jurors. Using the same real-world cross-examination techniques, and building upon the findings of Study Two, Study Three qualitatively explored mock jurors and juries’ understanding, perceptions, and use of alibi evidence as part of the deliberative process within a simulated criminal trial. The novel findings demonstrated that participants were overarchingly sceptical of alibi evidence and evaluated the defence through the lens of non-evidential factors, with an idealistic (yet unrealistic) expectation for complete consistency between and within accounts. Together, the thesis has achieved a concerted and triangulated understanding of such discrete, yet interdependent, aspects, producing novel knowledge that is invaluable to barristers, jurors, juries, and the Criminal Justice System.