Prior to imposition of a Class I or Class II disciplinary action, an Accusation shall be prepared and signed by the chief of the department, the Mayor, or any citizen or taxpayer, stating the act, duty, conduct or situation causing consideration of disciplinary action and the reason or reasons which authorize the disciplinary action under the Civil Service Act. A copy of the Accusation shall be delivered to the employee either personally or by delivery to the employee's last known place of residence at least seventy-two (72) hours prior to imposition of the disciplinary action. The time and date of delivery shall be stated on the copy of the Accusation.