A citizen's arrest follows nearly the same procedure as an arrest by an officer of the law. The process of arrest includes the seizure and restraint of the presumably guilty party, and allows the person making the arrest to confiscate weapons. What makes a citizen's arrest notable is that it is carried out specifically by a private citizen, someone who is not an official member of law enforcement.
Requirements for a Citizen's Arrest
Citizen's arrests can only be executed under specific circumstances, which vary from state to state. You cannot perform a citizen's arrest because you dislike a person, or even because you suspect him of doing something illegal. The Arizona state legislature declares that a "private person" may make an arrest if he witnesses a felony or a "misdemeanor amounting to a breach of the peace," which includes, but is not limited to, theft, assault, harassment, cruelty to animals and disorderly conduct. A citizen's arrest may also be carried out if a felony has been committed and a private citizen "has reasonable ground to believe that the person to be arrested has committed it."
Method of Arrest
In carrying out a citizen's arrest, the person performing the arrest must notify the person being arrested of the cause of said arrest, as a police officer would do in that situation. The only cases in which this would not be done would be if the person being arrested attempted to "flee or forcibly resist," or if this information would put the arrest at risk. The person performing the arrest may not use "unnecessary or unreasonable force."
Rights in Performing an Arrest
During a citizen's arrest, you have the right to confiscate weapons on the arrested party's person. These weapons must be brought before the magistrate to whom the arrested party is taken. If a felony is committed in your presence, you also have the right to break into a building to perform a citizen's arrest on the perpetrator.
After the Arrest
After making a citizen's arrest, you must deliver the arrested party to a peace officer or the "nearest or most accessible magistrate in the county in which the arrest was made." If you take the arrested party directly to the magistrate yourself, you must issue a "complaint" in which you explain the arrested party's offense. You may be required to issue this complaint to the magistrate even if you take the arrested party to a peace officer, if the peace officer did not witness the arrest and cannot give a satisfactory account of it.