<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> <P> Dollree Mapp was an employee in the illegal gambling rackets dominated by Cleveland rackets kingpin Shon Birns . On May 23, 1957, police officers in Cleveland, Ohio, received an anonymous tip by phone that Virgil Ogletree, a numbers operator who was wanted for questioning in the bombing of rival numbers racketeer and future boxing promoter Don King's home three days earlier, might be found at Mapp's house, as well as illegal betting slips and equipment employed in the "California Gold" numbers operation set up by Mapp's boyfriend Edward Keeling . Three officers went to the home and asked for permission to enter, but Mapp, after consulting her lawyer by telephone, refused to admit them without a search warrant . Two officers left, and one remained, watching the house from across the street . </P>

What was the issue in mapp v ohio