Alibi Evidence in Criminal Investigations and Trials: Psychological and Legal Factors

Article excerpt


In a criminal investigation a variety of people potentially involved in the crime are often expected to remember their actions and whereabouts at the time of the event, and then to corroborate their recollection so that they can be ruled out as suspects. In other words, people are often expected to have an alibi to prove their innocence. Despite the often crucial role played by alibis, however, surprisingly little empirical research has been conducted on the issue from either a legal or a psychological perspective. This article reviews some of the legal issues regarding the evaluation of alibis in the justice system, and then goes on to discuss two relevant psychological aspects: (1) people's ability to accurately recall what they were doing at specific times in the past and (2) people's ability to adequately weigh alibi evidence in light of the many other factors involved in a case (e.g., race and socioeconomic status of the suspect, time since the event occurred). The article concludes with an optimistic prognosis on the future of alibi research.

Investigating people's claims about their actions and whereabouts at the time an event took place is a common theme in crime dramas and standard operating procedure in real cases. In any given case, odds are that several innocent people and at least one guilty person will provide police with a story that may be subsequently corroborated, not corroborated, or proven to be an outright fabrication when the claim is investigated. Although it seems a simple matter that such alibis can contribute directly to determining the guilt or innocence of an individual, there are many relevant legal and psychological issues that have not been addressed in any organized way until recently.

In its strictest sense, an alibi implies that an individual could not have committed the crime, as it would be physically impossible for him or her to have been in two places at the same time. But there is some confusion over whether the term "alibi" should be used merely for a person's claim that they were somewhere else (e.g., "his alibi is that he was in Winnipeg at the time of the murder in Moncton, but we'll see if it checks out"), a defence strategy that forces the trier of fact to weigh the claim against other evidence (e.g., "there is one witness who puts him near the scene at the time of the crime and another who puts him 20 kilometres away at the same time"), or if the term should be reserved for a claim that has been corroborated so that the person is no longer a suspect in the case (e.g., "he has an alibi for the night in question, so he must not be the offender"). This article looks at all three uses of the term and addresses issues relating to each case.

Legal Issues Regarding Alibis

Although some courts and legal scholars have addressed the issue of alibis, they have not done so in any systematic way. Connelly (1983), for example, discusses the distinction between an alibi that is judged to be false versus one which is proven to be so, as well as the acceptable inferences to be drawn about the guilt of the accused based on these false alibis. While jurors can use an alibi as corroborating evidence, an individual is not to be convicted solely on the basis of no alibi, or even on the basis of a fabricated alibi. Eldridge (1978) argues that ideally alibis should be considered as just another piece of evidence, despite the possible subtleties involved in judges and/or jurors determining the quality of an alibi (e.g., the credibility of those providing supporting testimony, their relationship to the accused, the ease with which supporting physical evidence could have been fabricated).

In the United Kingdom, Devlin (1976) attempted to differentiate between different types of alibis, in response to the question of when eyewitness evidence should be relied upon. Based upon the Devlin classification, if an alibi is deemed to be clearly false (fabricated), it could be considered supporting evidence to the identification. …