Federal prosecutors are preparing to charge several individuals and confiscate their property over the alleged looting of Venezuela’s state oil company in what may amount to one of the biggest asset seizures in U.S. history.

Three people familiar with the case say the government has been investigating at least a dozen Venezuelans and is expected to file charges in Houston against a few of them as soon as next month. Those on the list, including former executives of Petroleos de Venezuela SA, known as PDVSA, are suspected of having taken bribes from middlemen to award contracts at inflated prices, helping to siphon more than $11 billion out of the country.