An officer or member employed full-time by a law enforcement unit who:
(a) Is charged with and primarily performs the duty of custody, control or supervision of individuals convicted of or arrested for a criminal offense and confined in a place of incarceration or detention other than a place used exclusively for incarceration or detention of juveniles; or
(b) Has been certified as a corrections officer described in paragraph (a) of this subsection and has supervisory or management authority for corrections officers described in paragraph (a) of this subsection