Usually the police must obtain an arrest warrant to make an arrest. However, when there is no time to obtain a warrant even though the concerned police officer has probable cause to believe that a crime has been committed, he can make an arrest without an arrest warrant. Moreover, an officer can make warrant less arrest of individuals who commit crime in his very presence.
Though invalid arrest is not a defense to the prosecution yet evidence obtained pursuant to such invalid arrest without probable cause may not be admissible in evidence at the trial.
As soon as an arrest is made, the arresting officer must read out the Miranda warnings to the arrestee to apprise him of his immediate rights. These include the right to remain silent and the right to obtain the assistance of a counsel. In case Miranda warnings are not read over to an arrestee as soon as he is taken into custody, any statement that the arrestee makes after his arrest is liable to be excluded from the trial.
The police may however try to confirm the identity of the arrested person by organizing a line up of different individuals with the arrestee suspect included in the queue. A photo array including the picture of the arrestee amongst many others may also be shown to the arrestee. Thereafter the victim is called upon to identify the arrestee.
