A gay rights advocate who was integral in legalizing same-sex marriage in Florida was found dead in a landfill in what authorities are investigating as a homicide, the Tallahassee Police Department said Wednesday.

Jorge Diaz-Johnston, 54, the brother of former Miami Mayor Manny Diaz, had been last seen alive on Jan. 3, Tallahassee police said. Shortly after a missing person alert was issued for him Saturday, his body was found in a trash pile at a landfill in Baker, Fla, about 60 miles east of the Alabama border, according to the Okaloosa County Sheriff’s Office.