Former BART police Officer Johannes Mehserle was distraught but silent after he shot an unarmed passenger to death early New Year's Day, his partner testified Wednesday. "When I looked at Officer Mehserle, his forehead was extremely sweaty, his face was flushed and his eyes were big," Officer Jon Woffinden testified at Mehserle's preliminary hearing on a murder charge. "He didn't say anything. ... I told him that he needed to take a walk."