The most powerful body of Vietnam's ruling Communist party, the Politburo, has set up a special investigation into allegations of collusion with organised crime by more than 50 government officials.
A number of the officials, including two police colonels, are accused of accepting bribes and giving protection to a gang, whose alleged leader Nam Cam is under investigation on murder charges.
One senior former official Tran Bach Dang said the collusion was known to have been going on for years.
A BBC regional analyst says the case is deeply embarrassing for the Vietnamese authorities, and, as the scandal touches on ever more senior government figures, it risks undermining the Communist Party's campaign against corruption.
The man in charge of the investigation, Major General Nguyen Viet Thanh, has said those involved will be pursued, no matter how senior they are.
Correspondents say some believe the case could go to the very top.
From the newsroom of the BBC World Service