Virginia residents likely know that the Fourth Amendment to the U.S. Constitution protects against unreasonable searches and seizures, but they may not know that evidence obtained without a search warrant or probable cause was still admissible in state courts during criminal trials until the Supreme Court effectively created the exclusionary rule in 1961. However, deciding whether or not evidence was gathered within the boundaries established by the Fourth Amendment is often difficult for judges.
Criminal defense attorneys may seek to have evidence excluded when police officers lacked probable cause to conduct a search, failed to obtain a search warrant or exceeded the scope of a search warrant that had been validly issued. Prosecutors may ask judges to grant them an exception to the exclusionary rule if the evidence in question was in plain sight or the officers involved reasonably believed that exigent circumstances existed.
Defense attorneys could also use the admission of questionable evidence as the grounds to appeal a criminal conviction. Criminal defendants can not generally be tried twice for the same crime, but the Supreme Court ruled in 1988 that the double jeopardy rule does not apply when convictions are overturned for reasons other than guilt or innocence. However, prosecutors may be reluctant to retry a difficult case without crucial evidence.
When judges rule that police obtained evidence illegally, experienced criminal defense attorneys may seek to have any evidence discovered as a result of the improper police acts excluded also. Judges may rule subsequent evidence inadmissible under what is known as the fruit of the poisonous tree doctrine. Defense attorneys could advise their clients to be polite and cooperate with police officers, but they may also urge them to refuse any requests to conduct searches unless presented with a valid and signed search warrant.