Police on Thursday said 39-year-old Chu Bin, whose real name is Chu Dang Thanh, and his group were suspected to be using drugs inside an apartment in District 10.
All were subsequently detained, but Chu Bin was released following a fine, while four others remain detained.
Before he became a singer, Chu Bin was a national silver-medal Taekwondo athlete, and a martial arts trainer.
In 2007, he participated in the singing talent show Vietnam Idol and made it to the top 30. He has released several albums since.