The board of any park district may employ such engineers, attorneys, clerks and other employees as may be required, and may define and prescribe their respective duties and compensation. The members of the board and all officers appointed by them shall be conservators of the peace within and upon such parks, boulevards, driveways, and property controlled by such park district, and may make arrests on view of the offense, or upon warrants for violation of any of the penal ordinances of such park districts, or for any breach of the peace, in the same manner as the police in cities organized and existing under the general laws of the State.