If a person becomes an arguido, he automatically gains certain rights that a witness or suspect would not have. An arguido has the right to be accompanied by a lawyer when questioned. The investigating police may ask the arguido more direct accusatory questions, which would not be legal otherwise, but the arguido must be presented with whatever evidence is held against him or her, and unlike a witness has the right to remain silent, not to answer any question that may incriminate the person, and does not face legal action for lying.
Witnesses in criminal investigations are legally bound to co-operate with the police and do not have the right to silence and face legal actions if they lie. Because of the legal advantages, some individuals apply for arguido status to be given to themselves, e.g. when it would appear that the police suspect them but are trying to use their witness status to extract as much information as possible.
A person who has arguido status has not been formally accused of a crime, arrested or charged, and not all arguidos are subsequently charged. The police may ask a court to restrict an arguido's movement and oblige him to not leave the country. Arguidos cannot change their place of residence. There is no time limit on the status.