the ʺfruits of the poisonous treeʺ doctrine applies only to arrests and not searches
Such evidence is not generally admissible in court. For example, if a police officer conducted an unconstitutional (Fourth Amendment) search of a home and obtained a key to a train station locker, and evidence of a crime came from the locker, that evidence would most likely be excluded under the fruit of the poisonous tree legal doctrine. The testimony of a witness who is discovered through illegal means would not necessarily be excluded, however, due to the ``attenuation doctrine'' , which allows certain evidence or testimony to be admitted in court if the link between the illegal police conduct and the resulting evidence or testimony is sufficiently attenuated. It is believed that a witness who freely and voluntarily testifies is enough of an independent intervening factor to sufficiently ``attenuate'' the connection between the government's illegal discovery of the witness and the witness's voluntary testimony itself. (United States v. Ceccolini, 435 U.S. 268 (1978))
Fruit of the poisonous tree