405 ILCS 5/4-405
When, as a result of personal observation and testimony in open court, any court has reasonable grounds to believe that a person appearing before it meets the standard for emergency admission, the court may enter an order for the temporary detention and examination of such person. The order shall set forth in detail the facts which are the basis for the court's conclusion. The court may order a peace officer to take the person into custody and transport him to a facility. The person may be detained for examination for no more than 24 hours. If a petition and certificate, as provided in this Article, are executed within the 24 hours, the person may be admitted and the provisions of this Article shall apply. If no petition or certificate is executed, the person shall be released.
405 ILCS 5/4-405