Anser Mehmood ran a small trucking business in Bayonne, NJ. But Sept. 11 turned his life upside down. A Pakistani who had overstayed his visa, he was soon caught up in the post-attack terror scare. Arrested for his immigration violation, he said he was held incommunicado for months under high security in a Brooklyn federal jail, beaten and thrown against walls, and kept in a cell with the window painted over.