The complaint filed in the case contains a range of accusations about the actions of Leonard Briskman, the leader of the marshals unit. It says that assets were sold without public notice or competitive bidding, and that Mr. Briskman assessed the value of certain assets, found buyers through his “business contacts,” and kept a secret bank account to which government auditors had no access.

The lawsuit, a whistle-blower action filed in November under the Federal False Claims Act, was brought by Brian S. Aryai, a former federal agent and certified public accountant who worked for a government contractor that helped the Marshals Service, through its Asset Forfeiture Program, administer more than $2 billion in seized and forfeited assets.