WASHINGTON  Two former employees of Blackwater Worldwide have accused the private security company of defrauding the government for years by filing bogus receipts, double billing for the same services and charging government agencies for strippers and prostitutes, according to court documents unsealed this week.

In a December 2008 lawsuit, the former employees said top Blackwater officials had engaged in a pattern of deception as they carried out government contracts in Iraq and Afghanistan, and in Louisiana in the aftermath of Hurricane Katrina.

The lawsuit, filed under the False Claims Act, also asserts that Blackwater officials turned a blind eye to “excessive and unjustified” force against Iraqi civilians by several Blackwater guards.

Blackwater has earned billions of dollars from government agencies in the years since the Sept. 11 attacks, when the company won contracts to protect American diplomats in Iraq and Afghanistan. The former employees who filed the lawsuit, a married couple named Brad and Melan Davis, said there was little financial oversight of the money.