“Fruit of the poisonous tree” is a legal doctrine concerning evidence against you that is obtained by the police illegally. According to Cornell University Law School, evidence gained as a result of an illegal method may not be admissible in court. In this metaphor, evidence that is obtained illegally is the tree, and anything that grows from that tree is therefore poisonous.
Say for example, you are pulled over for a traffic violation and the police search your car illegally. During the search, they find drugs and drug paraphernalia. Under the fruit of the poisonous tree doctrine, since the search was done illegally (the tree), the drugs and drug paraphernalia may not be admissible in court (the fruit that grew from the tree).
This doctrine is closely related to the exclusionary rule, which states that evidence obtained in violation of your Fourth Amendment rights may not be used in a criminal trial. The purpose of both the exclusionary rule and the fruit of the poisonous tree doctrine is to deter police from utilizing illegal methods to obtain evidence.
“Fruit of the poisonous tree” is a legal doctrine concerning evidence against you that is obtained by the police illegally.
There are, however, three important exceptions to this doctrine. The evidence may still be used against you if:
- It was discovered independently from the illegal activity.
- The chain between the illegal activity and the discovery of the evidence is too weak.
- It was inevitable that it would have been discovered eventually.
This doctrine applies not only to physical evidence, but to testimony as well. So if you are interrogated by police illegally, anything you subsequently say or confess to may also not be admissible.