Ala. Code § 22-50-21
The State Mental Health Officer may appoint or employ one or more suitable persons to act as police officers to arrest intruders, trespassers, and persons guilty of improper or disorderly conduct on the property of state mental health facilities or hospitals. Such officers shall be charged with all the duties and invested with all the powers of police officers and may eject trespassers from the hospital grounds, buildings, or lands or arrest them and may, without warrant, arrest any person guilty of abuse of a patient, of a misdemeanor or disorderly conduct, of stealing or injuring property or other offenses committed on the lands or premises of the hospitals and take such person before a district court judge or other officer charged with trial of such offenders, before whom, upon proper affidavit charging the offense, the person so arrested shall be tried and, if found guilty, convicted as in cases of persons brought before such a court on a warrant. Such police officer shall have authority to summon a posse comitatus.
Ala. Code § 22-50-21 (1975)