sentences:  The Shadow Wolves' primary task is tracking smugglers through a stretch of the Tohono O'odham Nation territory that runs along the Mexico–United States border in the state of Arizona.The "Shadow Wolves" law enforcement unit was created in 1972 by an Act of Congress, after the U.S. federal government agreed to the Tohono O'odham Nation's demand that the officers have at least one fourth Native American ancestry.The Shadow Wolves became the first federal law enforcement agents allowed to operate on Tohono land.