Napolitano told The Arizona Republic's editorial board on Friday that 40-year-old Brian A. Terry's elite team was tracking the 'rip crew' Tuesday when a gunbattle erupted in a remote southern Arizona canyon just north of the Mexican border.
Other agents arrested four suspects and continue searching for a fifth.
Napolitano says the organized bandits being tracked by Terry's team typically target drug smugglers or illegal immigrants making their way into the U.S.
Napolitano's remarks were the first official confirmation of what occurred during the late-night confrontation. Officials with the Border Patrol union have previously described the encounter.