WASHINGTON — The company that handled a background check on National Security Agency leaker Edward Snowden allegedly defrauded the government by submitting at least 665,000 investigations that had not been properly completed, and then tried to cover it up when the government suspected what was going on.

That company is U.S. Investigations Services (USIS), which has offices in Boyers, Butler County, and Grove City. It is based in Falls Church, Va.

The number of investigations, the Justice Department said today in a civil complaint, amounts to 40 percent of the cases that the company, USIS sent to the government over a four-year span, continuing through at least September 2012.

In response, the company said that integrity and excellence are core values at USIS, which has 6,000 employees.

USIS was involved in a background investigation of Snowden in 2011, but his particular job doesn’t figure in the lawsuit.

The government said that USIS engaged in a practice known inside the company as “dumping” or “flushing.” It involved releasing uncompleted background cases to the government and representing them as complete to increase revenue and profit.

The government paid the company $11.7 million in performance awards for the years 2008, 2009 and 2010, according to the Justice Department court filing.

USIS senior management “was fully aware of and, in fact, directed the dumping practices,” the government complaint said.

Beginning in March 2008, USIS’ president and CEO established revenue goals for the company. USIS’s chief financial officer determined how many cases needed to be reviewed or dumped to meet those goals, the complaint added.