Special counsel Robert Mueller has run into some skepticism from the federal judge overseeing the case he brought against Russians allegedly behind a social media campaign to influence the 2016 election — skepticism that could lead to the dismissal of the count against a company run by the Russian oligarch known as Putin’s chef.

The company, Concord Management, surprised observers by hiring lawyers to show up in court to fight the charges. Mueller has already survived Concord Management’s challenge to his legal authority to prosecute the case. Now U.S. District Judge Dabney Friedrich is weighing a motion by Concord Management seeking to throw out one count of conspiracy to defraud the United States on the basis of that indictment itself doesn’t allege an actual crime.

The issue is a complicated point of criminal law, but it could jeopardize the only count in the indictment that implicates Russian oligarch Yevgeniy Viktorovich Prigozhin. Concord Management, along with Prigozhin and his other company Concord Catering, are alleged to have funded the internet trolling effort, and have been charged with one count of conspiracy to defraud the United States. Unlike Concord Management, Prigozhin has not submitted to the court’s jurisdiction and is not actively defending the case.

In a troubling sign for Mueller, Friedrich on Thursday evening ordered prosecutors to file more briefings on the conspiracy to defraud the United States count. The judge’s order came after a hearing Monday, where she grilled prosecutors on what they would need to prove in court.

“If Congress wanted to prohibit any foreign involvement in an election, they could do it, but they didn’t do that,” Concord Management’s attorney Eric Dubelier said at a hearing Monday. “They carved out what you can’t do. They never said to foreign people you can’t talk and say what you want to say about a political candidate in the United States.”

The hearing centered on two of the three government agencies Concord Management is explicitly alleged to have defrauded, the Justice Department and the Federal Election Commission. Mueller alleges Concord Management, along with other defendants named in the indictment, conspired to impede the ability of the Justice Department to enforce the Foreign Agents Registration Act — which requires people who are lobbying in the U.S. on behalf of foreign individuals or entities disclose that lobbying — and the ability of the FEC to administer its ban on foreign expenditures in elections, under the Federal Election Campaign Act (FECA) .

Concord Management is arguing that Mueller has not shown in the indictment that the Russians knew about their legal obligations under those regulations, which according to Dubelier is required to bring criminal charges under the law, and is using the conspiracy charge as a workaround.

“They don’t have the evidence to charge a substantive violation of FARA or a substantive passport violation or a substantive FECA violation, because there is no evidence anywhere that any of these foreign people knew anything about any of these laws or regulations, none,” Dubelier said at the hearing.

Prosecutors argued that to bring the conspiracy count, all they need to show is that defendants had some knowledge that the government regulated those areas and that they took actions to impede that enforcement through acts of deception.

“It doesn’t matter if they knew it was the FEC or the DOJ or some other agency,” Mueller prosecutor Jonathan Kravis argued Monday. “They know that there is a lawful government function here, and they are acting with a purpose of interfering with it.”

Kravis pointed to the Russian trolls’ alleged move to disguise not just their identities, but the origin of the computer networks they used to influence the election on social media.

The deception there wasn’t just directed at the Facebook user reading their posts, who wouldn’t see the network information, but was “deception that is directed at a higher level,” Kravis said.

Dabney, in her order Thursday night, is now asking for prosecutors to square their arguments during the hearing with what’s alleged in the indictment. She specifically pointed to lines in the indictment about defendants’ alleged failure to report their lobbying to the Justice Department or their expenditures to the FEC. She also noted the case law prosecutors cited that she said, in doing so, showed them conceding that they have to show that the defendants had a duty to report.

“Should the Court assume for purposes of this motion that neither Concord nor its co-conspirators had any legal duty to report expenditures or to register as a foreign agent?” Friedrich asked in the order. “Specifically, should the Court assume for purposes of this motion that neither Concord nor its co-conspirators knowingly or unknowingly violated any provision, civil or criminal, of FECA or FARA by failing to report expenditures or by failing to register as a foreign agent?”

If the conspiracy charge that Concord Management is attacking is thrown out, other charges in the indictment will stand against other Russian individuals and companies. The Internet Research Agency — the organization that according to Mueller, employed the social media trolls — was charged with conspiracy to commit bank fraud and wire fraud, as were two individual Russians. Internet Research Agency along with four Russian individuals, have also been charged with aggravated identity theft.

Neither Prigozhin nor his companies are charged in those counts.