If the defendant had a mental disease or defect, and, as a result, is incapable of knowing the nature and quality of the act or that the act was wrong, then the defendant may be found not guilty by reason of insanity. The burden is on the defense, and there is a presumption of sanity. If found not guilty by reason of insanity, the defendant is subject to a civil commitment hearing.
Diminished capacity is a lesser version of the insanity defense. It is not a complete defense, as insanity, but is evidence of mental or emotional conditions that show the defendant could not form the state of mind required to commit the crime. Voluntary intoxication is the same, a defense showing that the intent to commit the crime cannot be formed. Diminished capacity and voluntary intoxication are available as defenses to specific intent crimes, but not general intent crimes.
Unconsciousness or automatism is also a similar defense, in that the defendant asserts that they were unable to physically control their actions. Voluntary intoxication cannot trigger this defense, and the burden is on the defendant.
An alibi defense is simple in its composition – it is evidence that the defendant was somewhere else when the criminal act was committed. The evidence directly contradicts the prosecution’s assertion that the defendant was present and committed the alleged action. The prosecution must discredit the defendant’s alibi, otherwise the jury will have to weigh it in light of the reasonable doubt burden.
An alibi instruction should be requested in order to preserve the issue on appeal. If co-defendants are joined for trial, an alibi defense of one of the co-defendants does not preclude the joinder, unless the conflicts between the co-defendants would deny one of the defendants a fair trial.
Like other defenses, notice must be given to the State of the intent to offer an alibi defense within 20 working days after the case is set for trial. Upon motion by the State, the defense may be ordered to disclose the identity of the alibi witness no later than two weeks prior to trial. With good cause, the State may be ordered to disclose any rebuttal witnesses prior to one week before trial (the parties may agree to a different time period).
The prosecution will attack certain aspects of an alibi defense. Impeaching the defendant by their prior statements, searching records establishing the defendant’s presence, the credibility of the alibi witnesses, and their motivation to testify will all be contested at trial.
Double jeopardy is a Constitutional protection, preventing a second prosecution of the defendant for the same offense. Offenses are not the same if an element of one offense is not present in the other offense.