SINGAPORE — A polytechnic student masterminded a scam on online marketplace Carousell that duped 147 victims who wanted to buy mobile phones into paying him a total of $360,600. Teo Jun Hao then went to Thailand with his ill-gotten gains and used the money to gamble. Teo, 24, and his then girlfriend Vanessa Chew Shi Qing, 26, were arrested at...