NEW : U.S. agency sends investigative team to help . The FBI is sending a new team of agents and investigators to the Middle East in an effort to find out what happened to three Americans who disappeared there last year. Mexico 's interior minister and two high-ranking officials among those killed . Interior minister is country 's second most-powerful post .
NEW : U.S. agency sends investigative team to help . Death toll in Mexican plane crash rises to 13 , report says . Mexico 's interior minister and two high-ranking officials among those killed . Interior minister is country 's second most-powerful post .