If it is necessary to ensure that a person appears before the court, the legal authority or the criminal police authority to which this action would be delegated issues an order to that person to appear which shows the identity of the person and the date, time and place at which he must present himself and specifies the penalties for failure to appear without due cause; this warrant is served on the party concerned at least three days in advance unless grounds for urgency are provided. Witnesses are given notice to appear at the judgement hearing. Pursuant to article 145 of Law 144/99, on International Judicial Cooperation in Criminal Matters, mutual assistance in criminal matters comprises the service of documents; the taking of evidence; searches, seizures and examinations; the hearing of suspects, defendants, witnesses or experts; and providing information about portuguese criminal law and about criminal record. When required by the circumstances, and subject to an agreement between Portugal and a foreign state or international judicial entity, hearings may be carried out using real time telecommunication, under the conditions laid down by Portuguese criminal procedure law. Under article 154 of the same law, the request for intervention in foreign proceedings as a suspect, accused, witness or expert has no mandatory effect and the person concern may refuse attendance. Where the summoning for witness entails any threat of sanctions the Portuguese authorities must reject such request.