Mexican officials say three Texas siblings, found dead in northeastern Mexico this week, had been tied-up and shot in the head.<br/> <br />Tamaulipas attorney general Ismael Quintanilla, says their suspected abduction earlier this month might have been orchestrated by local security officials.<br/> <br />(SOUNDBITE) (Spanish) ISMAEL QUINTANILLA, ATTORNEY GENERAL OF THE BORDER STATE OF TAMAULIPAS, SAYING:<br/> <br />"We are giving instructions to the agents from the public prosecutor's office so that investigations continue and people who need to be called upon for a statement are called and go on until we are able to find those responsible and remand them."<br/> <br />The investigation comes amid a search for another 43 missing students -- thought to have been abducted with the help of police.
