U.S. Immigration and Customs Enforcement tactical officer Kevin Carlos removes a packet of some 500 lbs. of marijuana confiscated on January 18, 2011 in the Tohono O'odham Nation,
Arizona. Carlos is a member of the Shadow Wolves, the only Native American unit of the U.S. Immigration and Customs Enforcement agency. The ICE unit tracks and interdicts drug smugglers and illegal immigrants crossing into the Indian reservation along a 72-mile stretch of the U.S.-Mexico border. The reservation is a key crossing point for narcotics entering the United States