The parents of the 43 forcibly disappeared students of the Ayotzinapa teacher training school have not given up on their demand to search for their loved ones on military bases. As federal officials continue to backtrack on their January promise to permit such a search, mounting evidence indicates some degree of military participation in the crimes committed against the students in Iguala, Guerrero, last September 26. Parents also point to documentation of the historic precedent of military participation in disappearances of activists, union leaders and guerrillas during the "dirty war" that began in the 1960s and continued for several decades. Clayton Conn reports for teleSUR