Washington (CNN) Michael Flynn's cooperation deal with prosecutors appears to be in jeopardy, according to court filings newly unsealed Tuesday in a case involving Flynn's former lobbying partner that's set to go to trial next week.

Prosecutors in the Eastern District of Virginia say they no longer trust President Donald Trump's former national security adviser and will not call him to testify against Bijan Kian, according to the court filings. They had said for months that Flynn would be their star cooperating witness.

But after statements his attorneys made to them in recent weeks, the prosecutors instead hope to tell the jury about Flynn's actions as an unindicted co-conspirator in the foreign lobbying case, according to the filings. Kian's trial will examine his and the Flynn Intel Group's allegedly illegal secret lobbying work for the government of Turkey.

The change in the prosecutors' trial plan is a dramatic, eleventh-hour shift in the case, and one that calls much of Flynn's future in court into question.

Following his 2017 plea, Flynn told two separate judges under oath that he had lied to federal authorities and accepted responsibility for his crimes.

Robert Mueller's prosecutors gave him a lenient sentencing recommendation, suggesting to Judge Emmet Sullivan in DC that he should face no jail time. But after Sullivan reacted harshly to such a high-ranking federal official lying, Flynn asked to postpone his sentencing so he could help prosecutors as a witness at the upcoming trial of Kian.

During the trial preparation, Flynn switched legal teams. His new attorneys -- including Sidney Powell, who has been sympathetic to anti-Mueller conspiracy theories -- told the Virginia-based prosecutors he hadn't intentionally made a false statement in a foreign lobbying disclosure in 2017. They have attempted to place some blame on his former legal team, from the law firm Covington & Burling, which cut his deal with Mueller and worked on his firm's foreign lobbying disclosures.

But Flynn's revised approach was a problem for prosecutors. It contradicted his plea deal admissions, they implied in an email to Kian's team.

"We do not necessarily agree with these characterizations" from Flynn's legal team, prosecutor James Gillis wrote to Kian's attorneys on July 2, according to an email revealed in court Tuesday. The prosecutors then pulled Flynn from their witness list in the Kian trial.

Federal prosecutors from Washington, who oversee Flynn's cooperation agreement, haven't yet weighed in on the developments. They are set to discuss them with Sullivan in a court submission Wednesday. It's possible they will give the judge a more negative review of Flynn's ongoing cooperation than they did before.

"The government has belatedly realized what should have been clear all along -- Flynn is not to be believed," Kian's lawyers wrote in another court filing unsealed Tuesday. "In short, Flynn wants to benefit off his plea agreement without actually being guilty of anything."

Flynn's attorneys wrote in court papers that despite their statements, they still believe Flynn is being helpful to the prosecutors. They explain his changed statement as coming with "the benefit of hindsight," meaning he hadn't realized when he signed the foreign lobbying form that he was lying, but later did.

"Flynn hired the FARA (Foreign Agents Registration Act) experts and followed the law," Powell told CNN on Tuesday. "Gen. Flynn is still cooperating."

They've also argued to the judge that the prosecutors' recent moves will hurt Flynn and shouldn't be allowed, according to more unsealed filings Tuesday.

"Mr. Flynn delayed his sentencing before Judge Sullivan to continue his cooperation here, for whatever benefit -- if any -- that might have in his sentencing, but he could have chosen not to cooperate further, proceeded to sentencing, and be done with all of it. The government should not be allowed to place him in a worse position now and name him as a co-conspirator in this proceeding -- for the feeding-frenzy of the press or for any future use it might contemplate," his attorneys wrote.

Flynn's lawyers were told Sunday night that prosecutors wanted to consider him an unindicted co-conspirator at the upcoming trial. The judge hasn't ruled yet on whether the prosecutors can do this, nor finalized whether they can use Flynn's statements to them at trial if he is not called as a witness.