The U.S. Border Patrol is monitoring millions of American drivers nationwide in a secretive program to identify and detain people whose travel patterns it deems suspicious, The Associated Press has found. The predictive intelligence program has resulted in people being stopped, searched and in some cases arrested. A network of cameras scans and records vehicle license plate information, and an algorithm flags vehicles deemed suspicious based on where they came from, where they were going and which route they took. Federal agents in turn may then flag local law enforcement.