The appointing authority may not bring charges recommending the imposition of discipline more than 90 days after the Intelligence and Investigative Division or the appointing authority acquires knowledge of the action that gives rise to the discipline. The 90–day limitation established under subsection (a) of this section does not apply to charges that relate to criminal activity if the criminal activity: relates to the correctional officer’s official duties; arises from events that occur at a correctional facility; or involves an incarcerated individual or detainee at a correctional facility. An appointing authority may not recommend disciplinary action against a correctional officer for excessive use of force against an incarcerated individual based solely on the uncorroborated statement of the incarcerated individual unless the appointing authority determines that there exists any indicia of reliability to support the incarcerated individual’s allegation. This section does not limit the right of the Department to investigate claims of excessive force against incarcerated individuals to ensure the safety and security of its correctional facilities, or for any other legitimate purpose.