sentences:  The two Americans were later reported to be Central Intelligence Agency agents, who were investigating a kidnapping.In early October 2012, there was strong evidence that the two CIA agents were victims of a targeted assassination attempt, as the Mexican Federal Police agents may have been working for the Beltran Leyva Cartel; however, it is one of several lines of investigation being conducted by Mexican officials.The US is the largest source of illicit traffic of weapons to Mexico.