search, the evidence may be brought forth in court. Good faith exception: If police officers acting in good faith (bona fides) rely upon a defective search warrant, then the evidence acquired may still be used under the good-faith exception. Independent Source Doctrine: If police obtain evidence illegally, but also obtain the same evidence through an independent, legal means, the evidence is admissible. Knock-and-Announce Exception: Evidence that police obtain in violation of the requirement to knock and announce themselves before searching a home is admissible. Attenuation : If the passage of time or intervening events break the causal relationship between the illegal activity and the evidence, the evidence may still be admissible. Some examples include: If a defendant was illegally arrested, but returns to the police station voluntarily several days later and makes a statement, the statement may be admissible. If a defendant was illegally stopped, but a valid outstanding arrest warrant is later discovered, evidence obtained during the stop may be admissible. Formerly, the Silver Platter doctrine allowed state officials that obtained evidence illegally to turn over evidence to federal officials, and have that evidence be admitted into trial. However, the doctrine was ruled unconstitutional in Elkins v. United States in 1960. The exclusionary rule is not applicable to non-U.S. nationals residing outside of U.S. borders. In United States v. Alvarez-Machain, the U.S. Supreme Court decided that property owned by aliens in a foreign country is admissible in court. Certain persons in the U.S. receive limited protections, such as prisoners, probationers, parolees, and persons crossing U.S. borders. Corporations, by virtue of being, also have limited rights under the Fourth Amendment (see corporate personhood). In the case of Florida v. Jimeno, it was found that the evidence found to convict Jimeno, although at first was not admissible, later was found to in fact be admissible since it passed the test of reasonable standards. The defendant consented to a search of his car, and when the officer searched a package and found drugs, it was not said to be in violation because a reasonable person would expect illegal narcotics to be kept in a package or container. Parallel construction The Special Operations Division of the U.S. Drug Enforcement Administration advises DEA agents to follow a process of parallel construction when launching criminal investigations of Americans based on SOD tips that may be based on warrantless surveillance. Criticism and defense The exclusionary rule