Alibi

An alibi is a defense in criminal law that the defendant was somewhere else when the alleged crime occurred, making it impossible to have committed it. In common usage, an alibi can also refer to any assertion that one could not have been involved in an event, though in legal terms it is narrowly about location at the time of the offense.

Etymology: the term comes from Latin alibi, meaning elsewhere, and entered English via legal usage to indicate that the accused was not present at the scene.

In legal practice: Raising an alibi requires evidence or testimony placing the defendant at a different location. The prosecution bears the burden to prove guilt beyond a reasonable doubt, but an effective alibi can create reasonable doubt about the defendant's presence at the scene. Some jurisdictions require notice of an alibi defense within a set period to allow investigation and disclosure of alibi witnesses and records.

Evidence and corroboration: Alibi support can come from witnesses who observed the defendant at a specified place and time, travel documents, surveillance video, phone location data, credit card transactions, or other records showing location. The strength of an alibi depends on its corroboration and credibility; a self-serving claim without independent support is often weak.

Limitations: An alibi is not an automatic shield; it must be consistent with the crime's timing and circumstances. If the prosecution presents credible evidence that the defendant could have been at the crime scene, the alibi may be undermined, and conviction can still occur if guilt beyond a reasonable doubt is established.