What does the "fruit of the poisonous tree" doctrine involve?

The "fruit of the poisonous tree" doctrine refers specifically to the principle in criminal law that any evidence derived from illegal searches or other unlawful actions by law enforcement is inadmissible in court. This doctrine aims to discourage police misconduct by ensuring that illegal evidence does not lead to the conviction of a defendant.

When evidence is obtained through illegal means, such as a violation of a person's Fourth Amendment rights (unreasonable searches and seizures), any further evidence derived from that initial illegal evidence is also tainted and considered inadmissible. This concept underscores the importance of adhering to constitutional protections during police investigations and reinforces the need for lawful procedures in obtaining evidence.

In contrast, evidence obtained through legal means would not fall under this doctrine as it is acquired legitimately and can be used in court. Similarly, testimony provided by police witnesses or conclusions drawn from jury deliberations do not relate to this doctrine since they do not directly pertain to the legality of the evidence's acquisition.