<Tr> <Td_colspan="2"> This case overturned a previous ruling or rulings </Td> </Tr> <Tr> <Td_colspan="2"> Wolf v. Colorado (1949) </Td> </Tr> <P> Mapp v. Ohio, 367 U.S. 643 (1961), was a landmark case in criminal procedure, in which the United States Supreme Court decided that evidence obtained in violation of the Fourth Amendment, which protects against "unreasonable searches and seizures," may not be used in state law criminal prosecutions in state courts, as well as in federal criminal law prosecutions in federal courts as had previously been the law . The Supreme Court accomplished this by use of a principle known as selective incorporation; in Mapp this involved the incorporation of the provisions, as interpreted by the Court, of the Fourth Amendment which are applicable only to actions of the federal government into the Fourteenth Amendment due process clause which is applicable to actions of the states . </P> <Table> <Tr> <Td> </Td> <Td> This section needs additional citations for verification . Please help improve this article by adding citations to reliable sources . Unsourced material may be challenged and removed . (October 2017) (Learn how and when to remove this template message) </Td> </Tr> </Table>

What was the issue in mapp v. ohio
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