Michael Flynn, former national security adviser to President Trump, walks into thefederal courthouse in Washington in July. (Jim Lo Scalzo/EPA-EFE/Shutterstock)

President Trump’s former national security adviser deserves no jail time for lying to the FBI about his contact with a Russian diplomat because he quickly took responsibility for his actions and cooperated with federal investigators, his lawyers said in a court filing Tuesday.

Lawyers for Michael Flynn acknowledge he did not tell the FBI the whole truth about his conversations with a Russian ambassador in early 2017, when the bureau was looking intoRussian interference in the presidential election. But, they said, he quickly agreed to cooperate when special counsel Robert S. Mueller III first asked him for information and ultimately sat for 62 hours of interviews.

Flynn agreed to plead guilty to a felony of making a false statement even in light of later reports that FBI officials involved in his case were themselves under investigation for misconduct, the lawyers said.

The filing comes a week after Mueller recommended that Flynn serve no prison time, citing his “substantial assistance” with several ongoing investigations.

Flynn is one of five Trump aides who have pleaded guilty in the special counsel probe. He was forced out of his post as national security adviser in February 2017 after the White House said he misled administration officials about his contacts with then Russian Ambassador Sergey Kislyak.

Flynn’s lawyers recommended U.S. District Judge Emmet G. Sullivan give their client a sentence of probation and community service. They argued Flynn is a highly decorated public servant who provided 33 years of exemplary service in the Army.

“General Flynn devoted his career to serving and protecting the Nation,” attorneys Robert Kelner and Stephen Anthony wrote in the 178-page filing. “Having made a serious error in judgment, for which he has shown true contrition, he recognized it was consistent with the values by which he has led his life simply to provide the facts to those charged with enforcing our laws.”

The filing included extensive testimonials from 50 friends and colleagues, including a letter from Frank Larkin, former U.S. Senate sergeant-at-arms and Navy SEAL.

Larkin spoke of Flynn’s integrity and commitment to his “warrior” family. He recalled Flynn being the first to knock on his door to offer sympathy when Larkin lost his son to suicide.

“Mike has never forgotten where he has come from and those that he has served with during his long stellar and respected career,” Larkin wrote to Sullivan. “This situation does not degrade the great man that he is or detract from the thousands of lives that he has truly impacted in interest of our national security.”

Since last year, Flynn has been cooperating with Mueller’s investigation into Russian interference in the 2016 campaign, and Mueller credited him with helping federal investigators with at least three major investigative threads.

One is a criminal investigation, the subject of which was entirely redacted from Mueller’s explanation to the court last week. A second is the special counsel’s investigation of possible coordination and links between Trump transition officials and Russia. There is at least one more Special Counsel probe, the subject of which has not been disclosed publicly.

Much of Flynn’s value as a witness to Mueller remains unknown to the public. Some of it has been shared with Sullivan, who will decide what sentence Flynn should serve, and what leniency he deserves as a result of his cooperation.

Staff writer Spencer S. Hsu contributed to this report.