Miss. Code Ann. § 45-3-9

(1) The chief of patrol, directors, inspectors, assistant inspectors, patrol officers and investigators of the department shall be selected after an examination as to physical and mental fitness, knowledge of traffic laws, rules and regulations of this state, the laws of the state pertaining to arrest, and the rules and regulations of the Mississippi Department of Public Safety and Public Service Commission, such examination to be prescribed by the commissioner. At the time of appointment they shall be citizens of the United States and the State of Mississippi, of good moral character, and shall be not less than twenty-one (21) years of age and shall have a high school diploma or High School Equivalency Diploma.

(2) Sworn agents of the Mississippi Bureau of Narcotics who are employed as enforcement troopers shall retain all compensatory, personal and sick leave accrued pursuant to Sections 25-3-92 , 25-3-93 and 25-3-95 .