An extension of the exclusionary rule established in Silverthorne Lumber Co. v. United States, 251 U.S. 385 (1920). This doctrine holds that evidence gathered with the assistance of illegally obtained information must be excluded from trial. Thus, if an illegal interrogation leads to the discovery of physical evidence, both the interrogation and the physical evidence may be excluded, the interrogation because of the exclusionary rule, and the physical evidence because it is the “fruit” of the illegal interrogation. This doctrine is subject to three of important exceptions. The evidence will not be excluded (1) if it was discovered from a source independent of the illegal activity; (2) its discovery was inevitable; or (3) if there is attenuation between the illegal activity and the discovery of the evidence.
Fruit of the Poisonous Tree
The essence of a provision forbidding the acquisition of evidence in a certain way is that not merely evidence so acquired shall not be used before the Court, but that it shall not be used at all. Of course, this does not mean that the facts thus obtained become sacred and inaccessible. If knowledge of them is gained from an independent source they may be proved like any others, but the knowledge gained by the Government's own wrong cannot be used by it in the way proposed.
Silverthorne Lumber Co. v. United States, 251 U.S. 385 (1920).