In some cases, the evidence obtained unconstitutionally may be exempted from the exclusionary rule. At these times, even if the situation meets the three criteria for the exclusionary rule to apply, the evidence will be admitted into court.
The three exceptions to the exclusionary rule
The first of such exceptions is the Independent Source Doctrine, which was brought into effect by the Supreme Court in 1984. The doctrine applies for two different ways for seizure of evidence; while one is clearly illegal, the other is done from within the confines of the law. For instance, if a person was suspected to be guilty of embezzlement, and someone was to Xerox his financial records without a proper warrant, the copies would not be allowed in court. However, if he later returned with a warrant and copied the records again, the new copies would be exempt from the exclusionary rule.
The inevitable discovery doctrine is the second case where the exclusionary rule is inapplicable. The exception was added following the Nix vs. Williams case in 1984. Of the two different ways of evidence seizure in this exception, only one is physical. The physical means of acquiring the evidence is also illegal, but a hypothesis exists of the seizure, which is not illegal. If a person was murdered and the suspect was illegally made to confess the body’s location, this would be an illegal physical seizure. If the prosecution can show that, there was already an ongoing search for the body when the suspect was thus made to confess, then they can also prove that hypothetically they would have discovered the body even if not for the forced confession; this is the legal hypothetical seizure. If the hypothetical seizure can be shown, then the evidence is exempt from the exclusionary rule by virtue of its being inevitably discovered.
The last exception to the exclusionary rule is the one of good faith. If a police officer gets a warrant from the magistrate, and subsequently seizes evidence, even if allowing him the warrant was in error, then the evidence will be allowed in court. This is because the exclusionary rule is in place primarily to prevent misconduct by the police, and if the magistrate or any higher body is convinced that such will not take place, the exclusionary rule does not apply in the case.
This is some information on the exceptions to the exclusionary rule. Further information can be referenced from online legal resource websites.