The US Department of Justice (DOJ) dropped its charges Thursday against Michael Flynn, the former National Security Advisor to President Donald Trump, for falsifying statements to the FBI.

The DOJ dropped the case after determining that Flynn’s statements were not “‘material’ to the underlying investigation.” Flynn made the statements during the FBI’s investigation of Russian election interference. The DOJ remarked:

In the case of Mr. Flynn, the evidence shows his statements were not “material” to any
viable counterintelligence investigation—or any investigation for that matter—initiated by the FBI. Indeed, the FBI itself had recognized that it lacked sufficient basis to sustain its initial counterintelligence investigation by seeking to close that very investigation without even an interview of Mr. Flynn. … Having repeatedly found “no derogatory information” on Mr. Flynn … the FBI’s draft “Closing Communication” made clear that the FBI had found no basis to “predicate further investigative efforts” into whether Mr. Flynn was being directed and controlled by a foreign power (Russia) in a manner that threatened U.S. national security or violated FARA or its related statutes.

The DOJ charged Flynn under 18 USC § 1001 for falsifying statements to federal officers about his conversation with the Russian ambassador, Sergey Kislyak during the investigation in 2016 Russian collusion. Section 1001 requires that the false statement be “material” to the investigation to warrant prosecution. The DOJ clarified, “‘Material’ requires that Materiality, moreover, requires more than mere ‘relevance’ or relatedness to the matter being investigated; it requires ‘probative weight,’ whereby the statement is ‘reasonably likely to influence the tribunal in making a determination required to be made.'”

In this case, Flynn admitted to falsifying statements about the nature of his phone call with Kislyak. According to transcripts, however, Flynn’s conversation with Kislyak regarded foreign policy and strengthening sanctions towards Russia. This foreign policy discussion was not “material” to the Russian election interference probe. Therefore, the DOJ could not prosecute Flynn under § 1001 for falsifying statements over the conversation.

The DOJ originally charged Flynn with falsifying statements to the FBI, and Flynn pleaded guilty to those charges in 2017. A federal judge postponed Flynn’s sentencing in 2018 due to Flynn’s cooperation with federal investigators in the Mueller probe.