The Fourth Amendment of the United States Constitution guarantees the right to be secure against unreasonable searches and seizures. It provides that warrants for an arrest or for a search shall be based on probable cause, shall be supported by an oath or an affirmation, and shall describe with particularity the placed to be searched or the person or thing to be seized. A search warrant is a written document that is signed by a magistrate or a judicial officer. The search warrant allows the police to conduct a search and describes the property that may be seized. The search warrant must be based upon probable cause. Probable cause means that an offense has been committed and that there is evidence in the place to be searched with regard to the offense. A general search under a search warrant is not allowed. The search warrant must specifically describe where the search is to take place, whom is to be searched, and what type of property is to be searched or seized. The description of the location of the search must be sufficiently definite so that a wrong location will not be searched. However, an error with regard to an address does not necessarily make the search warrant invalid. The search warrant must be signed by the magistrate or the judicial officer in order to be valid. In order to obtain a search warrant, a police officer or another peace officer appears before a magistrate or a judicial officer and signs a document that is made under oath and that sets forth the reasons for the search. The police officer or the other peace officer usually writes the search warrant and only presents the search warrant for the signature of the magistrate or the other judicial officer. It is the magistrate's duty to see that the search warrant satisfies the appropriate requirements and that it is based on probable cause. A search warrant may be used to search for and seize property that is stolen, property that is used in the commission of a crime, weapons, drugs, gambling materials, and other contraband. The search warrant may also be used to search people, to take photographs of people, and to obtain medical evidence from people such as blood and urine samples. A search warrant may be issued along with an arrest warrant. If it is combined with the arrest warrant, the magistrate or the other judicial officer must determine whether there is probable cause for both the search warrant and the arrest warrant. The arrest warrant can be determined to be invalid while the search warrant can be determined to be valid. The search warrant can be determined to be invalid while the arrest warrant can be determined to be valid. Evidence that is obtained under an invalid search warrant is subject to being excluded as evidence at trial under the "exclusionary rule." This rule provides that illegally obtained evidence cannot be used at trial. Evidence that is obtained under an invalid search warrant may be challenged by an accused in a motion to suppress evidence. Whether the search warrant is valid and whether the evidence may be used against the accused is determined in a suppression hearing before a judge.