Alibi is a masculine noun in Portuguese, relating to a proof or a testimony which aims to justify, defend and prove the someone's innocence, freeing him from the guilt.
In a legal context, an alibi can be considered a "tool" by the defendant to prove his innocence, during the investigation process of a criminal trial, for example. An alibi can be a document, a photograph or a person who has the ability to challenge an allegation.
For example, in the case of a crime, when the accused (the defendant) presents an alibi, he is able to prove that he has not he was at the place or time when the situation that incriminated him happened, making it impossible for him to be the criminal.
The expression "perfect alibi" is used when someone presents indisputable proof of innocence, in a situation where they are accused of something unlawful or unfair.
Example: "The defendant presented an alibi that proves his innocence".
According to article 156 of Criminal Procedure Code:
"The proof of the allegation will be up to whoever makes it, being, however, allowed to the judge of office:
(...) II determine, in the course of the instruction, or before issuing a sentence, the carrying out of steps to resolve doubts on a relevant point.
The subject under study was questioned in the contest of the Magistracy/DF in 2006 with the following correct statement:
O alibi, negative evidentiary evidence of authorship, whose burden is on the defense, can have its veracity verified in steps determined ex officio by the judge".