In the case of Wong Sun v. United States, 1962, the U.S Supreme Court ruled that verbal evidence and physical items obtained during an unlawful invasion by law enforcement could not be used in court as they were "fruits of a poisonous tree". This term refers to evidence acquired through illegal means or violations of constitutional rights. The case involved narcotics-related charges against several individuals including Wong Sun. Law enforcement had arrested them based on uncorroborated tips and without warrants, violating their Fourth Amendment rights against unreasonable searches and seizures. The Court held that statements made by defendants outside of custody but still under the influence of an illegal arrest are also inadmissible as evidence due to being tainted by the initial illegality.

The dissenting opinion in the case of Wong Sun v. United States, argued that the majority's decision to exclude evidence obtained through verbal statements made during an illegal arrest was too broad and could potentially hinder law enforcement efforts. The dissenters believed that while physical evidence seized unlawfully should be excluded from trial, verbal statements should not necessarily fall under this rule as they are a product of free will rather than coercion or force. They also expressed concern over potential difficulties in determining whether certain pieces of evidence were fruits of unlawful actions by police officers. Furthermore, they contended that excluding such evidence might encourage criminals to make false claims about their arrests being unlawful just to have validly obtained incriminating evidences dismissed.