“Fruit of the poisonous tree is a legal metaphor in the United States used to describe evidence gathered with the aid of information obtained illegally.” The “poisonous tree” whose image is taken from Matthew 7:17-20 is an illegal search; the fruit is the evidence procured thereby which, due to its association with the illegal search, is, by corollary, inadmissible. What this means in concrete terms is that if law enforcement officials have no probable cause to suspect that a law is being violated, they cannot verify their suspicions by a search. For instance, if you are pulled over for speeding, your speeding cannot be used as a pretext to search your vehicle for illicit substances.
The appropriation of marijuana during a traffic stop for a damaged blinker did not result in an arrest for drug possession, as the marijuana was fruit of the poisonous tree.
The consequence of the exclusionary rule which is known today as “fruit of the poisonous tree” comes from Silverthorne Lumber Co. v. Untied States. Silverthorne Lumber Co., under investigation for tax evasion, was subjected to a warrantless search by government officials during the detainment of the company heads. Not only was the search conducted without a warrant, it was not limited to materials that were immediately relevant to the case. The district court kept copies made of the evidence so obtained, but ordered the return of the originals to Silverthorne. When subpoenas again requested the surrender of the original materials, the defendants refused and were found in contempt of court. However, because the materials seized illegally, they qualified as fruit of the poisonous tree; and the contempt charge was thrown out.
Other Important Information
While fruit of the poisonous tree cannot be used to determine a defendant’s guilt or innocence, it may sometimes be used to impeach a party’s credibility.