When you face criminal charges, the Fruit of the Poisonous Tree Doctrine could well play a major role in your defense. Consequently, you would do well to understand this doctrine and the way in which it works.
As FindLaw explains, the Fruit of the Poisonous Tree Doctrine goes hand in hand with the exclusionary rule, the rule that requires courts to exclude incriminating evidence against the defendant that the prosecution obtained in violation of the Fourth Amendment.
Metaphoric Rule
No, the Fruit of the Poisonous Tree Doctrine does not deal with either fruit or trees. Rather, this is a metaphor that takes the exclusionary rule one step farther. It states that not only must the court exclude the illegally obtained evidence itself (the poisonous tree), but also any other evidence (fruit) derived from it.
Fourth Amendment
Both the exclusionary rule and the Fruit of the Poisonous Tree Doctrine get their legality from the Fourth Amendment. This Amendment states:
“The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.”
Its whole purpose, and that of the rule and doctrine stemming from it, is to guard against overzealous law enforcement investigations where officers seize people or property without a warrant authorizing them to do so. Therefore, if officers arrest you or seize your property without a warrant, or in violation of it, your attorney can move to have anything they obtained excluded from evidence, making your conviction much less likely.