Vietnam Coast Guard found vessel at 2330 hrs on 4 October, about 9 nautical miles Southeast from Vung Tau.
The TG 90389-TS vessel, which used fake number BV 90389-TS, was transporting 130,000 litres of diesel oil.
Captain could not produce sufficient documents to prove legality of 3 million litres of gasoline onboard.
Vietnam Coast Guard escorted BPP3 to Phu Quoc port to conduct further investigations and verification.
Pacific Ocean under instruction by Singapore firm Far East Shipping & Trading Pte Ltd, says local media.
Two fishing boats - TG 94457 TS and TG 94456 TS - detected displaying numerous suspicious signs which prompted inspection by the Vietnam Coast Guard.
8,150 m3 of A95 gasoline found on Pioneer Spirit while QNG 0350 carried about 350 m3 of similar product.
Ng Hock Teck, Tan Cheng Chuan, and Doan Xuan Than were charged at a Singapore court on Saturday.
