sentences:  The unit is congressionally authorized to have as many as 21 members but, as of March, 2007, it consisted of only 15 members.Members of the unit come from nine different tribes, including the Tohono O'odham, Blackfeet, Lakota, Navajo, Omaha, Sioux, and Yaqui.In 2003, the Shadow Wolves became part of the Department of Homeland Security when ICE was merged into Homeland Security.