The U.S. Department of Justice hit two contractors with multi-million dollar fines this week, after an investigation concluded Russian computer scientists were writing software code for U.S. military systems.

Computer Sciences Corporation (CSC) and its subcontractor NetCracker agreed to pay more than $12 million in a settlement with DoJ, which alleged the contractors’ negligence allowed Russian programmers to infect the Department of Defense with several viruses, reported the Center for Public Integrity.

“From 2008 through 2013, NetCracker allegedly used employees without security clearances to perform work when it knew the [Defense Information Systems Agency] contract required those individuals to have security clearances, resulting in CSC recklessly submitting false claims for payment to DISA,” DoJ said in a statement Monday.

The settlement came as a result of a civil suit brought by former NetCracker employee and whistleblower John Kingsley on behalf of the United States, in which he confirmed Russian involvement in U.S. military software production. He’ll receive a $2.4 million payout, and the DoJ reserves the right to press criminal charges.

“On at least one occasion, numerous viruses were loaded onto the DISA network as a result of code written by the Russian programmers and installed on servers in the DISA secure system,” Kingsley’s complaint read.

NetCracker and Computer Sciences Corporation have both denied Kingsley’s allegations.

DISA spokeswoman Alana Johnson refused to confirm to CPI the extent of Russian involvement in writing code for the US military. She did say the allegations are “something that we take very seriously.”

Outsourcing programming work to Russian employees violated “the company’s contract and federal regulations that mandate only U.S. citizens with approved security clearances work on classified systems,” Johnson added.

CSC representative Heather Williams distanced the contractor from NetCracker, referring to CSC as just “as much a victim of NetCracker’s conduct” as DISA.

NetCracker is a telecommunications firm, while CSC is an information technology corporation. CSC had the primary contract with the Pentagon to manage the communication system and NetCracker was a CSC subcontractor.

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