Definition
A defense in a criminal prosecution by which the accused asserts that he or she was in a different location at the time the alleged crime was committed, making it physically impossible to have been the perpetrator. The term derives from the Latin word for "elsewhere." Setting up an alibi means introducing evidence — typically testimony, records, or other proof — establishing the accused's presence at a place other than the crime scene during the relevant time window.
The alibi is not an affirmative defense in the traditional sense; it does not excuse or justify the act. Rather, it negates the prosecution's case by attacking the factual premise that the accused was present when and where the crime occurred. A successful alibi leaves the jury unable to place the defendant at the scene and, combined with the prosecution's burden of proof beyond a reasonable doubt, compels acquittal.
The alibi must account for the entire period during which the offense could have been committed. Partial coverage — placing the defendant elsewhere for only part of the relevant time — is generally insufficient if the crime could have occurred within the unaccounted interval.
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Common Language
Modern common usage (Wiktionary): "An excuse, especially one used to avoid responsibility or blame."
Historical common usage (Webster's 1913): "The plea or mode of defense under which a person on trial for a crime proves or attempts to prove that he was in another place when the alleged act was committed."
The common meaning has drifted far from the legal one. In everyday speech, "alibi" has become a general synonym for any excuse or cover story — a fabricated explanation for being late, missing a meeting, or avoiding blame. In law, alibi is a precise factual claim about physical location, not a rhetorical escape. Researchers encountering the term in legal sources should not import the colloquial connotation of deception or implausibility; a legal alibi is simply evidence of whereabouts, which may be entirely truthful and conclusive.
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Common Confusion
ALIBI vs. AFFIRMATIVE DEFENSE: Alibi is sometimes loosely grouped with affirmative defenses, but the distinction matters. An affirmative defense (self-defense, insanity, entrapment) concedes presence or action and offers a legal justification or excuse. An alibi denies the foundational fact of presence altogether. This distinction affects burden-shifting rules, notice requirements, and how jury instructions are framed. In many jurisdictions, alibi notice rules are separate from affirmative defense rules precisely because of this structural difference.
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Core Elements
For an alibi defense to be viable, the evidence must establish:
1. LOCATION: The accused was at a specific, identifiable place other than the crime scene.
2. TIMING: The accused was at that other place at the time the offense was committed — not merely nearby in time.
3. INCOMPATIBILITY: The distance or circumstances make it physically impossible or unreasonable that the accused could have committed the offense and been at the alibi location.
Courts have consistently held that the alibi must cover the window of time the crime was actually shown to have occurred, not merely the time charged in the indictment, to foreclose the possibility of commission.
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Why It Matters in Research
Notice requirements are a significant trap in modern research. Many jurisdictions require the defense to provide advance notice of an intent to rely on alibi, along with names of alibi witnesses, under rules modeled on Federal Rule of Criminal Procedure 12.1. Failure to provide timely notice can result in exclusion of alibi witnesses entirely. This procedural dimension does not appear in any of the historical dictionary sources, which treat alibi purely as an evidentiary concept. Researchers working with modern criminal procedure materials must track notice rules separately from the substantive definition.
The burden of proof question has a layered history. Historical sources (Anderson's, Burrill's) correctly state that the prosecution must disprove the alibi beyond a reasonable doubt — the accused need not prove the alibi, only raise it. However, some older American cases placed the burden on the defendant to establish alibi by a preponderance, a doctrine that was largely discredited and abandoned across most jurisdictions by the mid-twentieth century. Researchers using pre-1950 case law must account for this shift; a rule stated in an older source may reflect the now-rejected burden-shifting approach.
Corpus connections: Alibi intersects heavily with eyewitness identification evidence (misidentification is the most common reason a true alibi fails), with co-conspirator liability (where presence may not be required for culpability), and with the constitutional right to present a defense under the Sixth and Fourteenth Amendments. Research into alibi exclusions as a constitutional matter runs through a separate line of authority from ordinary evidentiary rules.
Jurisdictional variation in notice rules, reciprocal discovery obligations, and the treatment of late-disclosed alibi witnesses makes cross-jurisdictional research particularly hazardous in this area.
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Historical Dictionary Support
The historical sources are in close agreement on the core definition. Black's (both editions), Burrill's, and Anderson's all define alibi as a defense by which the accused proves presence at a different location, sufficient to negate guilt. The formulations are nearly identical, with Black's 1st and 2nd editions drawing directly on Tomlins, and Burrill's adding Foster's Crown Law and Wills on Circumstantial Evidence as supporting authority.
Anderson's is the most analytically useful of the historical sources on the evidentiary standard, explicitly noting that "to convict, the jury must be satisfied beyond a reasonable doubt that the accused was at the place charged" and that the alibi defense "must cover the time when the offense is shown to have been committed, so as to preclude the possibility" of commission. This framing correctly identifies that the burden remains on the prosecution — a point the other sources leave implicit.
What the historical dictionaries collectively omit: procedural notice requirements (a twentieth-century development), the constitutional dimensions of alibi witness exclusion, and any treatment of alibi in the context of accomplice or conspiracy liability where physical presence is not an element. Researchers should treat these sources as authoritative on the substantive definition but incomplete on modern procedural context.
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Jurisdictional Note
Federal Rule of Criminal Procedure 12.1 and analogous state rules require written notice of alibi intent, including witness identification, with deadlines set by the court. Reciprocal disclosure obligations typically require the prosecution to disclose rebuttal witnesses in return. State rules vary significantly in timing, specificity requirements, and sanctions for noncompliance, ranging from discretionary exclusion to mandatory preclusion.
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Encyclopedia Cross-Reference
Alibi Defense — The Law Mind Criminal Law Encyclopedia
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