Legal Question in Criminal Law in California

Generally, the police have to have a warrant to search a person's home. There are exceptions. If you gave them consent, they don't need a warrant. If you did not consent, and no applicable exception applies, they are supposed to show you the warrant. If you asked, and they refused, they most likely do not have a warrant.

There are many circumstances in which police are allowed to search a home without a warrant. If they don't have a warrant then they cannot be required to show it to you, even if the search is proper. But if the officers have a warrant and the owner or occupant asks to see it, they must show it to him.