The president of the university may appoint or employ one or more suitable persons to act as police officers to keep off intruders and prevent trespass upon and damage to the property of the university. Such person shall be charged with all the duties and invested with all the powers of police officers. The officer may eject trespassers from the university buildings and grounds. The officer may, without warrant, arrest persons who commit disorderly conduct, or trespass on the property of the institution, or in any circumstance in which an arrest by a police officer without a warrant is authorized by law, and carry them before the nearest district court or municipal court charged with the trial of such offenders. Upon proper affidavit charging the offense, the person arrested may be tried by the court and convicted as in case of persons brought before the court on a warrant. The officer or officers may summon a posse comitatus.