A California man was charged Monday with operating a ring of illegal test-takers who helped dozens of Middle Eastern nationals obtain U.S. student visas by passing proficiency and college-placement exams for them. Eamonn Daniel Higgins, 46, of Laguna Niguel made an appearance in U.S. District Court in Santa Ana on one count of conspiracy to commit visa fraud as immigration agents arrested 16 of his suspected clients who remained in Southern California... The allegations revealed a potentially dangerous security breach in the country's student visa system and underscored the vulnerability of a tracking process that relies on schools to verify...