An overcrowded tourist boat carrying Muslim pilgrims was being piloted recklessly before it capsized, killing at least 15 Thai people, officials said on Monday as divers and other rescuers searched for 11 people still missing. The accident happened on Sunday on the Chao Phraya River in Ayutthaya , The double-decker tourist boat carrying around 100 Thai Muslims on a pilgrimage tried to overtake a sand barge and ran into a barrier, police said, causing the boat to capsize. 11 people are still missing and police divers resumed their search early on Monday. No foreigners were believed to be among the dead. The boat was 50 passengers over its capacity at the time of the accident, police said .