(Markus Schreiber | AP)SEHNDE, Germany — A German national who is under investigation in the disappearance of British toddler Madeleine McCann 18 years ago was released from prison Wednesday after serving his sentence in an unrelated case, police said. But the suspect, who has denied any involvement in her disappearance, has not been charged in the case. He also remains a suspect in an investigation into McCann’s disappearance being conducted by Britain’s Metropolitan Police, who say he refused their request for an interview. Investigators in the U.K., Portugal and Germany are still piecing together what happened on the night 3-year-old Madeleine disappeared. A district court in the city sentenced him to six weeks in prison for that, but the defense has appealed.