Police in Tay Ninh Province have identified the son of the victims as the prime suspect, without naming him.
The son, after learning where his parents had stored the money, on March 10 informed three men—Dao Xuan Loc, 33, Nguyen Tuan Anh, and Nguyen Anh Duy, both 32, who then posed as police officers to arrive at the house and demand to inspect the origin of the foreign currency, investigation found.
The three men then asked the parents to accompany them to a police station for further questioning.
Believing the men to be legitimate officers, the parents agreed to go, preparing to prove the money's legitimacy. However, while the parents were distracted, the fake officers seized the money and fled.
The victims immediately reported the incident to the police.
All three robbers then fled the province, and arrest warrants were issued against them.
A source from the police told VnExpress on Monday that the three men have been arrested while hiding in Gia Lai Province, more than 500 km from Tay Ninh.
The source said they had been hiding in different places over the past two weeks.
Earlier the police have arrested two of their accomplices, and recovered the full amount of stolen cash.