He was in Mexico and attempted to cross the border without Advance Parole, he was aprehended by CBP and since he had left to Mexico for whatever reason and was trying to re-enter illegally, he was sent back across the border. That's what the government is saying happened. The Dreamer was saying he was first deported by CBP because they failed to verify that he had DACA, then he tried to re-enter ilegally from Mexico.