Fruit of the poisonous tree
Fruit of the poisonous tree is a legal theory in the United States that makes illegally obtained evidence, as well as subsequent evidence legally obtained if discovered solely as a result of the illegally obtained evidence, inadmissible in a court of law. This theory is a rational for applying the exclusionary rule to a certain piece of evidence. Several counter theories exist, such as the doctrine of attenuation. In the United States, defendants may make a motion to suppress such evidence, which means that the defendant is asking the trial judge to rule particular evidence inadmissible during trial.
For example, if a murder suspect was taken in for questioning but not read his Miranda rights, and subsequently confesses to the murder and provides authorities with the location of a victim's body (and the authorities obtain a search warrant and recover the body), neither the confession nor the body can be used against the suspect in criminal proceedings, unless the police can show that a) it was inevitable that the body would have been discovered anyways, b) that an independent source, such as a witness, had informed them of where the body was, c) the connection between the illegally obtained evidence and the subsequently discovered evidence was so weakened or stretched as to remove the "taint" of illegality, or d) the government's conduct was in "good faith."
The fruit of the poisonous tree doctrine is related to the exclusionary rule, which finds its origins in Weeks v. United States 232 U.S. 383 (1914), a case argued before the Supreme Court on December 2–3, 1913 which interprets the Bill of Rights. In Weeks v. United States, Justice William R. Day overturned Weeks's conviction because the evidence used against him at trial was obtained in violation of the Fourth Amendment, and ruled that the illegally obtained evidence could not be used against Weeks. The "traditionally" leading case on the Fruit of the Poisonous Tree doctrine is Silverthorne Lumber Co. v United States.
The exclusionary rule came about as a remedy for violations of suspects constitutional rights. However, some argue that it is ridiculous that a criminal go free "because the constable blundered."  While other remedies are conceivable, such as holding both the constable and the suspect accountable for their own actions and violations, in the United States, the exclusionary rule remains judicial precedent.
- Weeks v. United States, 232 U.S. 383 (1914) Created Exclusionary rule at federal level
- Mapp v. Ohio, 367 U.S. 643 (1961) Applied exclusionary rule to states
- ''Bivens v. Six Unknown Named Agents''
- See People v. Defore , 242 N. Y. 13, 21, 150 N. E. 585, 587 (1926), Cardozo J.