Sloan, Deputy Director Luther

Star Trek: Deep Space Nine
Episode: DS9 542 - Inquisition

Amoral agent in a secretive division of Starfleet Intelligence called Section 31 who repeatedly tried to recruit Dr. Julian Bashir into the covert agency. In 2375 Sloan committed suicide rather than give up the cure for the Founders Disease, but Bashir and Miles O'Brien recovered the information anyway.