What does the term 'fruit of the poisonous tree' refer to?

The term "fruit of the poisonous tree" is a legal metaphor used to describe evidence that is obtained as a result of illegal actions, typically by law enforcement. In other words, if the police obtain evidence through an unlawful act, such as an illegal search or seizure, any subsequent evidence that is discovered as a result of that initial unlawful action is also considered tainted and inadmissible in court. This doctrine is rooted in the principle that the government should not benefit from illegal actions.

This practice safeguards constitutional rights, particularly the Fourth Amendment right against unreasonable searches and seizures, by excluding not just the direct evidence obtained through misconduct, but also any additional evidence that flows from that misconduct. The rationale is that allowing such evidence could encourage law enforcement to engage in unlawful behavior, undermining the integrity of the legal system.

The other options do not align with the definition of this legal term. Option A refers to evidence acquired lawfully, which is admissible in court. Option C discusses confessions that are made freely, which are typically admissible unless obtained through coercive means. Option D regards evidence from expert testimony, which is unrelated to police conduct or the origins of evidence in this context.