defendant, Sergeant Gomez testified that "because he was very active in his calls, this led me to identify the  establish the illicit activities that he was participating in, the cocaine trafficking, the weapons trafficking that he was carrying out for the 16th front in his role as a main collaborator with Negro Acacio." (Trial Tr. PM Session 25, Mar. 17, 2010.) Sergeant Gomez went on to explain how he identified the name associated with the defendant's voice and said that "[i]nitially, Negro Acacio or Negro Acacio and his radio operator would call out on the air, `Chiguiro, Cheeky, Cheeky, Cheeky,' calling him, and this person would come up on the air and begin to participate in the calls." (Trial Tr. PM Session 25-26, 34, 38-39, 41-42, 43,Mar. 17, 2010.) He said that the voice he heard being referenced as Chiguiro was the same voice he heard in a series of calls that comprised Government's Exhibit 508T. He also said that during the time he monitored radio communications connected to the FARC he never heard anyone other than the defendant referred to as "Chiguiro." (Trial Tr. PM Session 26, Mar. 17, 2010.) Sergeant Gomez said that even if there had been two people using the same nickname in the 16th Front, he still "would have known which one was this Chiguiro." (Trial Tr. PM Session 43, Mar. 17, 2010.)
Sergeant Gomez also testified that the FARC used code words for their security during calls. (Trial Tr. PM Session 45, Mar. 17, 2010.) He explained that "[s]o,