Authorities face tough territory in border probe - Article Photos 9/13

U.S. Border Patrol agents stand on top of their vehicles and look into Mexico west of Douglas, Ariz., after a Border Patrol agent was shot and killed on Tuesday Oct. 2, 2012. One agent was killed and another wounded in the incident. (AP Photo/Arizona Daily Star, Benjie Sanders) ALL LOCAL TV OUT; PAC-12 OUT; MANDATORY CREDIT