The alibi defense doesn’t says that a crime didn’t occur. It says that if a crime occurred, someone else was the perpetrator The defense says that the defendant was not the perpetrator and was not at the scene but elsewhere.
The state has to prove the defendant committed the crime and was at the crime scene. So, the defendant need not raise the alibi. But, if alibi is asserted notice must be given to the state pursuant to Supreme Court Rule 413. Under S.Ct. Rules 413(d)(iii) and 415, the state must be given notice of the alibi defense. Moreover, there is a continuing obligation to provide information. If you don’t, you run the risk of having a witnesses’ testimony barred.
When an alibi defense is raised, evidence of the defendant’s whereabouts, other than at the scene of the crime at the time of the offense, is admissible. But, evidence that tends to establish the guilt of another person is also admissible.
The defense can expect their witnesses to be attacked and their credibility to be questioned. Corroboration is important and circumstantial evidence independent of the witnesses is helpful.
Documents or items of physical evidence that tend to support the witnesses can be invaluable. Consistency among witnesses is extremely important and any gaps need to be explained properly.
Most assuredly, the relationship of witnesses to the defendant and inconsistencies in time, place, and details will be questioned. If the defendant was at a football or hockey game, the witnesses should know who was playing and what the score was. Preparation is always vital, but a good attorney should properly prep for cross-examination.