Final answer:
In circumstances where a seizure is conducted without probable cause, the exclusionary rule prohibits the use of illegally obtained evidence in criminal trials.
Step-by-step explanation:
If the police conduct an illegal search or seizure without a warrant and find evidence of a crime, the exclusionary rule may apply. This rule, established by the Supreme Court in cases such as Mapp v. Ohio, ensures any evidence obtained illegally cannot be used in a state criminal trial. This includes not only the direct evidence seized but also any evidence that was found as a result of the illegal search or seizure.
For example, if police entered a home without a warrant or probable cause and found illegal substances, the substances, and any additional evidence their discovery led to, could not be used to prosecute the homeowner. However, there are exceptions to the exclusionary rule, such as if the police acted in good faith believing their search was legal, or if the evidence would have been inevitably discovered by lawful means.