where did they steal it from?
Wiki:
According to Cambodian Royal Chronicles as compiled by Ros Chantrabot, the legends state that after remaining in Pataliputra for three hundred years, The Emerald Buddha was taken to Sri Lanka to save it from a civil war. The emerald Buddha then somehow arrived in Cambodia, giving its name place known as Russey Keo.[7] When the Thais attacked Angkor Wat in 1432 (following the ravage of the bubonic plague), the Emerald Buddha was taken to Ayutthaya, Kamphaeng Phet, Laos and finally Chiang Rai, where the ruler of the city hid it until it was found in 1434.[4]