(a) Any law-enforcement officer or public official responsible for keeping the peace may issue a command to disperse in accordance with this section if he reasonably believes that a riot, or disorderly conduct by an assemblage of three or more persons, is occurring. The command to disperse shall be given in a manner reasonably calculated to be communicated to the assemblage.
(b) Any person who fails to comply with a lawful command to disperse is guilty of a Class 2 misdemeanor.
(c) If any person remains at the scene of any riot, or disorderly conduct by an assemblage of three or more persons, following a command to disperse and after a reasonable time for dispersal has elapsed, it is prima facie evidence that the person so remaining is willfully engaging in the riot or disorderly conduct, as the case may be. (1969, c. 869, s. 1; 1993, c. 539, s. 190; 1994, Ex. Sess., c. 24, s. 14(c).)