Lawmakers from both sides of the aisle — and both chambers of Congress — are questioning a Department of Homeland Security contract for up to $190 million to a firm that the Justice Department accused of fraud.

Sen. Tom Coburn (R-Okla.) and Rep. Elijah Cummings (D-Md.) issued a letter to Homeland Security Secretary Jeh Johnson last week requesting documents and other information about the agency’s decision to award a contract to U.S. Investigations Services LLC for services related to the nation’s immigration system.

Sen. Tom Coburn (R-Okla.). (Kevin Lamarque/Reuters).

The Justice Department has accused the USIS of improperly reviewing its background checks of potential government employees and contractors in an effort to increase its revenues. Federal prosecutors allege that USIS submitted more than 600,000 incomplete reviews in a scheme known as “dumping.”

Despite the fraud claims, U.S. Immigration and Customs Enforcement rated the firm as “low risk,” according to the letter.

“The fact that a company can commit so many mistakes — including ones that jeopardize our national security — and be rewarded for their incompetence at a high price tells us yet again that our contracting system is broken,” Coburn said in a statement this month.

USIS spokesman Patrick Scanlan said the dumping allegations are contrary to the firm’s “values and commitment to exceptional service,” adding that they relate to a “small group of individuals over a specific time period and are inconsistent with the strong service record we have earned since our inception in 1996.”

Scanlan also said Homeland Security awarded the contract based on a “rigorous two-year competition” and that the work will be done by a division of the firm that “has not been linked in any way to the ongoing government investigation.”

USIS screened former National Security Administration contractor Edward Snowden, who leaked sensitive information about the federal government’s vast electronic surveillance activities, as well as former Navy contractor Aaron Alexis, who killed 12 people in the Washington Navy Yard shooting last year. The firm is not known to have handled their background checks improperly.

The Office of Personnel Management, which oversees background checks for federal employees and contractors, changed its policies in February so that contractors are no longer allowed to audit their own background checks. The agency said it would rely on its own staff to do the work.

The lawmakers asked that Homeland Security provide them with a briefing on the new USIS contract sometime next week.

Homeland Security and Immigration and Customs Enforcement did not respond to requests for comment on Tuesday.