| The Trump administration aggressively publicized the arrests of more than 8,000 immigrants by federal agents since Inauguration Day, with the promise that those detained would be part of a historic mass deportation. But NBC News has learned that some have already been released back into the United States on a monitoring program, according to five sources familiar with the operations. In a statement to NBC News, an ICE spokesperson acknowledged federal court cases limit the agency from detaining people indefinitely if their countries refuse to take them back, which can lead ICE to release them. | 