When most people think of an “arrest,” they envision a police officer cuffing criminal suspects and placing them in the back of a police cruiser. But there’s more to an arrest than taking a suspect into custody. Arrests trigger legal (and emotional) after-effects that include detailed and specific police responsibilities.
A person who reasonably believes that they are deprived of personal liberty and is not free to leave police custody is considered to be "under arrest." A suspect doesn’t need to be cuffed or physically restrained to be under arrest. Nor do the police have to announce the fact. What matters is whether a reasonable person in the same position would believe that they are not free to leave.
Consider a woman who drives to the police station and volunteers to answer questions. At some point, the woman stops answering questions and wants to leave. The police tell her she cannot leave the room until the questioning is finished and when she stands up, an officer motions with his hand for her to sit down. The police actions amount to an arrest.
Not all detentions by the police amount to an arrest. The police may detain an individual in order to issue a citation, for example, for minor traffic infractions or for some criminal misdemeanors. A citation, once signed by the suspect, amounts to an agreement, in lieu of an arrest, to appear in court at a later date. This temporary detention is permissible but is not considered an arrest (although it may still trigger the police officer’s right to search the suspect, as explained below).
An arrest occurs once the police have enough evidence to establish probable cause—a reasonable belief that the suspect has committed a crime. On TV, most arrests are usually made when a suspect is directly observed performing criminal activity and is arrested in the act (or immediately afterwards). In real life, there is often more time between the criminal act and the arrest, as the police investigate the details or as evidence is provided. As a general rule, arrests made at person’s residence require an arrest warrant and also require that the police “knock and announce” their purpose. However, these rules need not apply in urgent situations, such as when evidence may be destroyed or individuals are in danger. An arrest warrant is a court order issued by a judge, based upon statements made under oath (and establishing probable cause).
Every person who is arrested in the U.S. and who is questioned by police must be informed of their legal rights (known as "Miranda Rights," discussed below). In addition, once an individual is arrested, the police may search the person incidental to the arrest. That's because police officers have the right to protect themselves by searching for weapons and to protect the legal case against the suspect by searching for evidence that the suspect might try to destroy. This is even permitted when an officer arrests an individual for a minor offense that results in a citation and not an arrest.
If a police officer does not have probable cause to make an arrest, it is possible that a judge may declare that the evidence seized incidental to the arrest is inadmissible at trial.
If a suspect is under arrest (in police custody) and is being questioned (interrogated) about the criminal activity, the police must inform the suspect of certain Constitutional rights (known as "Miranda Rights"). These rights are summarized in the following statement:
"You have the right to remain silent. You have the right to have an attorney present when we question you, and if you cannot afford an attorney one will be appointed for you. If you waive these rights and talk to us, anything you say may be used against you in court. Do you understand these rights?"
A suspect need not be “Mirandized” if the suspect has not been arrested. The same is true if the suspect has been arrested, but has not been questioned. If a suspect refuses to answer questions after receiving a Miranda warning, the police may return—typically within two weeks—and provide the Miranda warnings again and see if they have better luck. If a suspect asserts rights under Miranda—for example, refusing to talk unless an attorney is present—statements elicited by the police without the attorney present would usually be inadmissible in court.
The only way to obtain freedom after an arrest is if the government dismisses charges against the individual, or, assuming that does not occur, if the suspect follows legal procedures that lead to freedom. These legal procedures may include releasing the suspect on bail, or a release based on the suspect’s own recognizance (“release O.R.”). And, of course, freedom may be obtained by proving the suspect’s innocence, or by entering into a plea bargain that permits release from custody.