Mai Thai An, 41, his wife Nguyen Thi Ngoc Giau, 38, and three accomplices are also being investigated for allegedly swindling money by offering to sell apartments without permits.
An and Giau received permits in 2020 to build a five-story house in Binh Chanh District, but illegally changed the design to add 12 rooms to take the total to 57, according to the police.
They partnered with brokers to advertise the rooms as apartments for sale.
But since the couple were not property developers, and therefore not allowed to sell parts of houses, they signed 50-year lease contracts with buyers instead.
The brokers they hired persuaded the customers by promising that all buyers would eventually get ownership documents and have the same rights as anyone buying a home.
A total of 57 contracts had been signed by the time of the arrests, and An and Giau had received VND50 billion in sales.