Jared Loughner, the young Tucson man accused of shooting Rep. Gabrielle Giffords and killing six people, is set to plead guilty Tuesday, an official familiar with the case said Saturday. A psychologist appointed by the court is expected to say at the hearing that he is competent to plead guilty, the official said. A previously scheduled status hearing has been changed to a change-of-plea hearing. In February, the psychologist said Mr. Loughner, a diagnosed schizophrenic, remained incompetent to stand trial. But she said at the time that the defendant was making progress toward competency, according to federal Judge Larry A....