December 10, 2004 — Last week’s arrest of a Bangladeshi immigrant trying to illegally enter the country has federal authorities concerned over the vulnerability of the U.S.-Mexico border to infiltration by terrorists. Federal court records show Fakhrul Islam, age unknown, was arrested Dec. 4 with 13 other undocumented immigrants as they tried to pass through a wooded area east of Brownsville. The records said a man later identified by Border Patrol agents as a member of the Mara Salvatruchas gang was traveling in the same group as Islam. The Central American gang has alleged links to al-Qaida. “This is alarming,”...