ASIS Professional Certified Investigator Practice Exam 2025 – Complete Study Guide

In Wong Sun v. US, the primary legal doctrine discussed is the fruit of the poison tree doctrine. This doctrine is an important principle in criminal law that pertains to evidence obtained through illegal means. It asserts that if the original evidence is tainted by a violation of a defendant's constitutional rights—for instance, through an unlawful search or seizure—any evidence gathered as a result of that initial misconduct is also considered tainted and inadmissible in court.

The case underscored this principle by determining that statements made by a suspect, following an illegal arrest, could not be used against them. This reinforces the idea that law enforcement must respect constitutional protections during evidence collection. The ruling emphasized that the legality of a search or seizure greatly influences the admissibility of subsequent evidence. Understanding this doctrine is crucial for investigators, as it directly impacts the integrity of the evidence they collect and their overall case strategy.

The other options represent distinct legal concepts that, while relevant in other contexts, are not the primary focus of Wong Sun v. US. The exclusionary rule pertains to the broader principle of excluding illegally obtained evidence, whereas Miranda rights relate to the requirement of informing suspects of their rights upon arrest. Double jeopardy deals with being tried twice for the same offense