The commissioners voted 3-2 Monday to reject the resignation of Bill Lee.
She cited a conflict of interest due to her husband's work relationship with potential defense attorney.
George Zimmerman appeared in court Thursday after being charged with second-degree murder in the shooting of Trayvon Martin.
Prosecutors charged Zimmerman with second-degree murder Wednesday in the deadly shooting of Trayvon Martin.
The controversial trial continues to fuel protests nationwide.
Screams heard on an emergency call are not Zimmermans, experts say.