Two Thai women, Apple Mingman and Thanyaluck Khotephoothorn, whom police alleged were accomplices to Matete Lebohang, were arrested earlier, Pol Colonel Somphorn Daengdee, a deputy TCSD commander, said.
A foreigner of unknown nationality was also wanted for his role in the racket, he said.
Police arrested Lebohang at a prison in northern Bangkok recently when he visited an inmate.
Somphorn said Lebohang hacked into the email of the unnamed three-star hotel and told the foreigners to wire him a total of Bt300,000.
Police said foreign conmen often befriend or marry Thai women to use them to open bank accounts to help them commit such crimes. Conmen often use these women to withdraw money from victims from cash machines to avoid detection by banks or ATM cameras, they said.