Final answer:
The silver platter doctrine allowed federal prosecutors to accept illegally obtained evidence by state law enforcement. This doctrine was an exception to the exclusionary rule until it was invalidated by the Supreme Court in 1960. Evidence obtained from an illegal act cannot be used in court due to the fruit of the poisonous tree principle.
Step-by-step explanation:
The doctrine that allowed federal prosecutors to accept illegally obtained evidence gathered by state law enforcement is known as the silver platter doctrine. This was a legal principle that permitted federal courts to admit evidence illegally seized by state police and handed over to federal authorities, metaphorically on a "silver platter." Although the exclusionary rule, established in the case of Weeks v. United States in 1914 and later applied to the states in Mapp v. Ohio (1961), prohibits the use of evidence obtained in violation of the Fourth Amendment, the silver platter doctrine served as an exception to this rule until it was overturned in 1960 by Elkins v. United States. The exclusionary rule is also known to cover the "fruit of the poisonous tree," which means that evidence obtained from an illegal search or seizure is also inadmissible.