The firm that screened contractor Edward Snowden before he leaked classified information about a controversial National Security Agency program has been under investigation since 2011.

Patrick McFarland, inspector general for the Office of Personnel Management, confirmed the probe during a Senate subcommittee hearing on the government’s security-clearance processes Thursday.

McFarland declined to provide specifics on the investigation of USIS, which claims to be the government’s largest provider of government background checks.

(J. Scott Applewhite/AP) - Sen. Claire McCaskill Sen. Claire McCaskill  (J. Scott Applewhite/AP)

Sen. Claire McCaskill (D-Mo.) said her office received information that the probe is a criminal investigation “related to USIS’s systematic failure to adequately conduct investigations under its contract.”

Subcommittee Chairman Jon Tester (D-Mont.) asked McFarland whether USIS may have failed to complete an appropriate and thorough screening of Snowden.

“Yes, we do believe that there may be some problems,” McFarland said.

USIS acknowledged in a statement Thursday that it had responded to a January 2012 subpoena from the inspector general’s office, but the firm did not confirm that it had investigated Snowden.

“USIS conducts thousands of background investigations annually for OPM and other government agencies,” the statement said. “These investigations are confidential and USIS does not comment on them.”

Susan Ruge, associate counsel to the inspector general, said on Friday that USIS’s re-screening of Snowden ended in April 2011 and that the IG began its probe of the firm later that year.

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