(a) On written request, a law enforcement officer may have expunged from any file the record of a formal complaint made against the law enforcement officer if:
(1) (i) the law enforcement agency that investigated the complaint:
1. exonerated the law enforcement officer of all charges in the complaint; or
2. determined that the charges were unsustained or unfounded; or
(ii) a hearing board acquitted the law enforcement officer, dismissed the action, or made a finding of not guilty; and
(2) at least 3 years have passed since the final disposition by the law enforcement agency or hearing board.
(b) Evidence of a formal complaint against a law enforcement officer is not admissible in an administrative or judicial proceeding if the complaint resulted in an outcome listed in subsection (a)(1) of this section.