ORLANDO, Fla. — In the weeks following Trayvon Martin’s shooting death a decade ago, hundreds of protesters took to the streets in Sanford demanding that the city reform its police department, which had long faced accusations of racial bias from members of the Black community. “There is a cancer within the (Sanford Police) Department that must be eradicated,” then-city Commissioner Velma Williams told a crowd at an April 2012 rally protesting the agency’s investigation of the Black teen’s killing and its decision not to immediately arrest shooter George Zimmerman. As Zimmerman remained free fo…