In criminal cases where a defendant has been apparently identified by witnesses or where evidence suggests that a particular defendant may have been the perpetrator, an alibi as a defense is commonly presented. In essence, the defendant is asserting that he could not have committed the crime because he was not at the scene when it occurred.
If presented as credible, this can be a powerful defense that can counter eyewitness testimony and circumstantial evidence that otherwise places you at the scene of the crime. Also, unlike self-defense or insanity, alibi is not an affirmative defense, which would require you to prove your defense by the civil standard of a preponderance of the evidence. This is often argued as proof that it is more likely than not that you acted in self-defense or lacked the mental capacity to have the requisite intent to be criminally liable.
For an alibi defense, though, you merely need to offer some evidence that is at least credible and which can place you at a different location when the crime occurred so that you could not have either been present or lacked the opportunity to commit the crime because you were engaged in some other activity.
In federal court and in many states, defendants have to notify the prosecutor in advance of trial that they intend to offer an alibi. This includes informing the prosecution of what the alibi is and how they intend to prove it such as by certain identified witnesses. California does not have a court rule that requires advance notice of an alibi, however, and the courts have left it to the legislature to enact one per Reynolds v. Superior Court, 12 Cal. 3d. 834, 529 P.2d 45 (1974). The legislature has not required such notice and some commentators have suggested that it would circumvent the defendant’s right against self-incrimination under the California Constitution.
In any criminal case, the prosecution has to turn over the evidence they have gathered in the case, whether incriminating or exculpatory. This includes statements of witnesses, medical records, photographs, investigative and police reports and lab or testing results. Likewise, defendants must turn over similar evidence including the names of witnesses they intend to call at trial. This gives the prosecution an opportunity to interview and take statements from these witnesses. Of course, some of these witnesses may be used to offer an alibi on behalf of the defendant.
Unless you are caught red-handed at the scene, most defendants will offer an alibi to show that because they were not at the scene at the time the crime was committed, they must be acquitted.
For instance, you are accused of murdering your spouse in your house and your fingerprints are found on a kitchen knife, that has been identified as the murder weapon. You may argue that you used that knife for cooking purposes so it was not unusual for your prints to be there and you can show that you were not at the house at the time the coroner placed the time of death. You may do this by introducing testimony from persons who were with you at the bowling alley. If there were video cameras there, you might obtain footage with the date and time stamped that place you at the bowling alley when the crime occurred.
Another scenario might be that neighbors heard you arguing with your spouse some time before the murder and that they recognized your voice. Your argument is that you left the house shortly thereafter and that your spouse has an intimate friend who should be a suspect. And, you have an alibi because you can produce receipts from a gas station indicating the place and time where you were when the murder occurred or even video footage.
An effective alibi needs to be credible. If you only present testimony from a family member or close friend or associate, a jury may question their credibility and assume their loyalty to you trumps the truth. Having persons testify who either do not know you or have at least limited social associations or connections with you will appear much more credible to the jury or judge.
My alibi can only be proved by testimony from my mother and siblings. Is this enough?
You can certainly argue, for instance, that it is natural for you to be home with your family but they have to be forceful and credible witnesses for you. Family members are usually not considered as believable compared to persons who barely know you and have no motivation for lying. You may need some other proof that you were at home when the crime occurred since as testimony from persons who talked with you on the phone, receipts from food delivery or other evidence.
I have been charged with conspiracy but I was not with the other defendant when he was arrested with certain incriminating evidence. Why am I still being charged?
The alibi defense does not work with conspiracy. Conspiracy is an agreement between at least two persons to commit a crime and that one of the parties to the agreement engaged in an overt act in furtherance of the crime. If you made an agreement to bomb a mall and the other party was arrested with explosives, ski masks, maps and other material consistent, then you may be arrested as a conspirator so long as the prosecution can prove you agreed to help. You can be in another state when either the crime was committed or the materials needed to commit the crime were found.
Does the alibi defense negate any element of a crime?
The prosecution still must prove all elements of the crime for which you are charged. You may well be conceding that a crime took place and all the elements of the crime were present, only that you were not the one who committed it. If the jury finds that your alibi is proved by eyewitness testimony or even video evidence, then you will likely be acquitted.
Is there other evidence that I could present to bolster my alibi?
Yes. For instance, your attorney might argue that eyewitness testimony identifying you was unreliable and that the description given of you fits other known offenders or persons who were previously under suspicion. Also, video or photographs or receipts with date and time stamped on them can be very compelling exculpatory evidence.