Although many people think that in order to arrest someone, the police must have an arrest warrant signed by a judge, this is not true in many cases. In fact, if the police have probable cause to believe that you have committed a crime, they can arrest you without obtaining an arrest warrant. However, the police must later show the court that at the time the arrest was made, there was sufficient probable cause.
You are probably wondering what probable cause means. Generally, probably cause exists when the police have more than a mere suspicion that a crime has been committed and that the person they wish to arrest is the person who committed that crime. The police do not have to see the suspect commit the crime. They just have to believe that it’s likely that the suspect was involved in the crime. For example, if a mugging victim tells the police he was held up at gunpoint by a man wearing jeans and a red shirt, and a block away the police find a man fleeing who fit the description, this is probably sufficient probable cause to justify an arrest.
However, police usually need a warrant if they are planning to arrest a suspect in the suspect’s home, although there are exceptions to the rule. Some exceptions include if an occupant in the house lets the police in, if there is a potential danger in the home, or when the police chased a suspect into his or her home.