Which case established the "Fruit of Poisonous Tree" doctrine?

The "Fruit of the Poisonous Tree" doctrine was established in the case of Brown v. Illinois. This legal principle asserts that evidence obtained illegally cannot be used in court. It builds upon the exclusionary rule, which excludes evidence collected in violation of a suspect's constitutional rights, particularly during unlawful searches and seizures.

In Brown v. Illinois, the Supreme Court emphasized that if the initial evidence acquired was tainted by an illegitimate action, then any further evidence derived from it would also be considered inadmissible because it is seen as "fruit" stemming from a "poisonous" source. This case helped to clarify the conditions under which derivative evidence could be excluded, underscoring the importance of ensuring that law enforcement adheres to constitutional safeguards to maintain the integrity of the judicial process.