Which Supreme Court case prohibited the police from conducting unreasonable searches and seizures and excluded illegally obtained evidence from state criminal trials?

Answer: Mapp v. Ohio

Explanation: Mapp v. Ohio is a supreme court that ruled the exclusionary rule, which prevents prosecutors from using evidence in court that was obtained by violating the Fourth Amendment to the U. S. Constitution. On June 19, 1961, the supreme court ruled that evidence obtained in violation of the Fourth Amendment to the U. S. Constitution, which prohibits "unreasonable searches and seizures," is inadmissible in state courts.