The US Department of Justice (DOJ) filed a motion on Monday to drop all charges against two Russian shell corporations accused of interfering with the 2016 presidential election.

The motion states, “the government has concluded that further proceedings promote[] neither the interests of justice nor the nation’s security.” The DOJexplained that, “sometimes in a criminal case, the government should ‘drop the charges if it fears that litigation presents unacceptable security risks.'” In this case, the DOJ fears that a trial could expose how the DOJ protects against foreign election interference.

The firms, Concord Management and Concord Consulting, were implicated by Special Counsel Robert Mueller III in his 2018 investigation and were accused of attempting to exploit the judicial system to gain access to information that could threaten national security. The two firms were joined by 13 Russians and a “troll farm”—an organization dedicated to spreading misinformation and affecting public opinion through provocative comments—dubbed the “Internet Research Agency.”

A grand jury indicted the Russian shells in February 2018. The firms were accused of acting under the Russian government to influence voter turnout during the 2016 presidential election.

The government is continuing its pursuit against others cited in the indictment.