HANOI, Vietnam — Police have arrested a bus driver who ignored warnings and went into a flooded area where the vehicle was swept away last week, leaving 20 people dead or missing, officials said Monday. The 35-year-old driver was taken into custody Saturday for violating traffic laws causing especially serious consequences, said Tran Van Long, deputy police chief of Nghi Xuan District in Ha Tinh province. The driver faces up to 15 years in prison if convicted. The bus was traveling from the central province of Dak Nong to the northern province of Nam Dinh on Oct. 18 when it was caught in surging currents after the driver ignored police warnings to stay away from the country’s flooded main highway. Rescuers later recovered the bodies of 15 passengers. Five others remain missing and are presumed dead. The driver and 17 passengers managed to swim to safety.