New details have emerged in Thailand's investigation of twin bombings in Bangkok on Monday and Tuesday which killed 20 people and left 125 more wounded, the Bangkok Post reported Wednesday.
According to Police Colonel Kamthon Ouicharoen, a bomb expert at the Metropolitan Police Bureau, the first bomb, which detonated near the Erawan shrine, was an improvised explosive device that looked like a model typically assembled abroad.
Assistant national police chief Prawut Thawornsiri said that an improvised pipe bomb was also used in the second attack at the Sathon pier. Thrown from the Taksin Bridge, it hit a pillar and fell into a canal where it detonated harmlessly.
Police Lieutenant Gen Prawut believes the bomber wanted to throw the device onto a busy walking platform, but missed. With a range of 30-50 meters, it had the capability to "inflict many casualties," Kamthon added.
The police bomb squad also found a number of 5-millimeter-diameter ball bearings scattered around the area, similar to those used by Iranian terrorists discovered assembling a bomb in Soi Sukhumvit in 2012.
Sources close to the investigation say it is focusing on a revenge motive by Uigher terrorists in response to the Thai government's deportation of Chinese Muslim migrants in July.
Top police officials as well as Thailand's prime minister have, however, remained mum on the subject of motive, urging the media to report responsibly and avoid causing more panic.
"Whether this incident was motivated by domestic politics or an international issue, I don't want to give you an opinion because it could mislead investigators and cause panic," Gen Prawut said Tuesday.
Police did admit, though, that they are searching for a "Middle Eastern-looking man," caught on a CCTV camera, who they are "more than 50% certain" was the bomber.
The footage shows a young, slightly built man wearing a yellow T-shirt, black-framed glasses and carrying a backpack. He is seen wandering around the shrine, sitting down, and leaving the area without his backpack.
Searches are being conducted in Nana sois 3 ,5, 9 and 11 - a neighborhood popular with Uigher migrants.