Fresh images emerge of the suspected masterminds behind the abduction of 43 student teachers in September -- all feared dead.<br/> <br />Mexican authorities are naming former mayor Jose Luis Abarca of Iguala and his wife Maria de los Angeles Pineda as key suspects.<br/> <br />Officials say he and his wife ordered police to stop 80 students from shaking up a political event in late September.<br/> <br />Investigators say police then handed over the students to drug gang Guerreros Unidos, who then killed and buried them in mass graves.<br/> <br />Their whereabouts remain unknown.