44-1-611. Tenure. Each person employed or appointed and designated as a chief, captain, lieutenant, sergeant, patrol officer, or any other rank under and pursuant to the provisions of this chapter, except as provided in 44-1-601 and 44-1-602, shall continue in service and hold the position without demotion until suspended, demoted, or discharged in the manner provided in parts 7 through 9 of this chapter for one or more of the causes specified in 44-1-612.