Generally, if there has been a 4th Amendment violation, then not only is that evidence suppressed, but also any evidence discovered as a result of that illegal conduct – this is known as the fruit of the poisonous tree doctrine. Here is an example – suppose officers conduct an illegal traffic stop (one without any legal basis for the stop). During the traffic c stop, the officers smell the odor of fresh marijuana, providing a basis for a search which results in 50 pounds of marijuana. Even if the actual search was a lawful probable cause search of a vehicle, the probable cause was obtained during an unlawful detention – and was the fruit of the poisonous tree (the initial illegal detention).
This rule has its exceptions, such as “independent source” and “inevitable discovery.” Those exceptions to this doctrine will be addressed in a subsequent post.
Legal Supplement
Murry v. U.S., 487 U.S. 533 (1988),
[T]he exclusionary rule also prohibits the introduction of derivative evidence, both tangible and testimonial, that is the primary evidence, or that is otherwise acquired as an indirect result of the unlawful search …
Wong Sun v. U.S., 371 U.S. 471 (1963),
Testimony as to matters observed during an unlawful invasion has been excluded in order to enforce the basic constitutional policies.
U.S. v. Shareef, 100 F.3d 1941 (10th Cir. 1996),
Defendants do have standing to challenge their detention. We distinguish passenger standing to directly challenge a vehicle search from passenger standing to seek suppression of evidence discovered in a vehicle as the fruit of an unlawful stop, detention, or arrest. If the physical evidence found in the vehicles was the fruit of the defendants’ unlawful detention, it must be suppressed.
