3. How Can an Illegal Search Affect My Criminal Case?

　　In Mapp v. Ohio （1961）, the Supreme Court established what has come to be known as the "exclusionary rule." This rule states that evidence seized in violation of the Fourth Amendment cannot be used as evidence against defendants in a criminal prosecution, state or federal. To this day, some commentators continue to criticize the Mapp case on the ground that it unfairly "lets the criminal go free because the constable has erred." But supporters of Mapp argue that excluding illegally seized evidence is necessary to deter police from conducting illegal searches. According to this deterrence argument, the police won't conduct improper searches if the resulting evidence is barred from the trial.

　　Case Example: Officer Joe Friday notices teenager Bunny Schwartz walking in a mall. Officer Friday demands to look into Bunny's purse. The officer finds three pairs of earrings with the price tags still attached. A mall jewelry store owner identifies the earrings as having been stolen minutes earlier, when Bunny was the only customer in the store. A judge rules that Officer Friday's search of Bunny's purse was improper.

　　Question: How will this ruling affect the case against Bunny?

　　Answer: The charges will have to be dropped. Because the search of Bunny's purse was illegal, the earrings are not admissible in evidence against her. As the prosecution has no case without the earrings, the case must be dismissed. Realizing that Bunny went free ought to deter Officer Friday from conducting illegal searches in the future, exactly what the exclusionary rule is supposed to accomplish.

　　4. If the Police Conduct an Illegal Search, Does the Case Against Me Have to Be Dismissed?

　　No. A judge will exclude evidence that the police seized or learned about as the result of an illegal search. But if a prosecutor has enough other evidence to prove the defendant guilty, the case can continue.

　　Case Example: Dick McCallous is charged with possession of stolen property—cleaning products stolen from a local janitorial supply business. Half of the missing janitorial products that McCallous is charged with possessing were discovered by the police at McCallous' home in the course of a warrantless search of the home by the police after they had properly arrested McCallous for possession of the other half. In response to a defense motion to exclude evidence, the judge rules that the police illegally seized the janitorial products from McCallous' home, but that the other products were seized properly.

　　Question: How will these rulings affect the case against McCallous?

　　Answer: The prosecution can go forward, limited to possession of properly seized stolen janitorial products.