The controversy surrounding House Intelligence Committee Chairman Devin Nunes may just be getting started. Nunes could soon be staring down the barrel of a House Ethics Committee investigation, lawyers familiar with the House’s rules tell The Daily Beast.

A few Republicans have already joined Democrats in calling for Nunes to either recuse himself from his committee’s probe into Russian influence—or to step down as chairman.

To add to this pressure, it appears that the chairman may have opened himself up to an ethics investigation by apparently disclosing the existence of a foreign surveillance warrant during a press conference last Tuesday.

Nunes’s problem lies in the arcane rules of the House of Representatives. Buried in the rules regarding the House Intelligence Committee is a section that triggers a mandatory investigation into an allegation of spilling classified information.

“The Committee on Ethics shall investigate any unauthorized disclosure of intelligence or intelligence-related information,” reads the rule. The key to this rule is the phrase, “shall investigate”—a command, rather than a mere suggestion.

“The plain wording of the rule is that the ethics committee is required to conduct such an investigation,” said Brett Kappel, an attorney that specializes in political law.

The trigger could be as simple as a complaint from a single member of the House of Representatives.

“If another member of Congress were to raise a written complaint about the actions of chairman Nunes, specifically his decision to disclose to the public information that is classified… the ethics committee would be required to conduct an inquiry,” explained Bradley Moss, a lawyer that specializes classification issues. A third attorney who specializes in this area of law but didn’t want to quoted on this topic agreed with this interpretation.

Nunes’ office did not address the topic of a potential ethics committee investigation, but insisted that the chairman did not spill classified information.

“The Chairman did not reveal any of the specific details of the information, such as the target of the collection, and did not reveal classified information,” said Jack Langer, a Nunes spokesman.

Last Wednesday, Nunes made to reporters what at first seemed like a bold, definitive claim: “I recently confirmed that on numerous occasions, the intelligence community incidentally collected information about U.S. citizens involved in the Trump transition.”

But things quickly grew murky from there. Nunes contradicted himself on several occasions: he first said the president’s communications were incidentally collected, then later walked it back to say it was merely possible; then Nunes said he didn’t know if the Trump transition team was surveilled or merely mentioned in intelligence reports.

But when asked if the information he obtained came from surveillance obtained under FISA, or the Foreign Intelligence Surveillance Act, Nunes replied, “it appears so.” He added, “it has to do with FISA, and there are multiple FISA warrants that are out there.”

Surveillance authorized by FISA is some of the government’s most highly-classified information. To some lawyers, that means there is credible evidence to suggest Nunes did reveal classified information by speaking about FISA surveillance—assuming he doesn’t walk the FISA claim back, of course.

“In my humble opinion, yes, Nunes disclosed classified information that day. The existence or non-existence of a FISA warrant is a classified fact. The details from the warrant, namely who got caught up in incidental collection, is a classified fact,” Moss told The Daily Beast. “Until we know who gave Nunes the info that night on the White House grounds, and until we have a resolution of the question whether the President authorized Nunes to disclose the details to the press, this is a question that cannot be answered definitively.”

As the national security lawyers at Lawfare note, information about FISA orders is classified until affirmatively declassified by the agency it came from.

“The way the system works is that it is classified until there is an affirmative decision to declassify it. So a leak or public disclosure doesn’t declassify it, and it doesn’t allow people who are aware of it to then discuss it publicly,” explained Susan Hennessey, a former lawyer for the National Security Agency.

Or as FBI Director James Comey put it last Monday during a House Intelligence Committee hearing chaired by Nunes, “All FISA applications reviewed by the court and collection by us pursuant to our FISA authority is classified.”

But Nunes might actually be saved from a probe due to the muddiness of his public statements.

“Because the language was so qualified, shifting in so many strange ways, it makes it very difficult to even parse out where we are. That said, generally, discussing FISA material is classified… he was discussing the collection of U.S. persons information, and he mentioned a U.S. person by name: President Donald Trump,” said Hennessey.

The House Ethics Committee had no comment when reached by The Daily Beast.

MoveOn.org, a progressive organization, has already filed a federal ethics complaint on this matter with the Office of Congressional Ethics, a separate body whereby outside groups can submit complaints. Only lawmakers can submit complaints to the House Committee on Ethics.

There are, however, limits to the rule requiring a House Ethics Committee investigation into classified information. The rule does not require any public disclosure of the investigation unless the allegations are substantiated, it does not outline exactly how extensive the investigation must be, and it doesn’t set out a mandatory timeline for investigation.

“My experience with the Ethics Committee is the staff wants to do, and does do, a thorough job. Whether that ever sees the light of day is another thing. There are many, many instances of the committee starting an investigation, and, somehow, it never finishes,” Kappel said. “If a member files a complaint, then they will [act].”

It’s hard to imagine that Nunes could have had a more difficult week than the one that has just passed. By Tuesday, the chairman of the House Intelligence Committee was facing demands from his fellow Republicans and conservatives to explain himself or recuse himself from the Russia investigation.

The saga began last Wednesday when Nunes made a shocking claim: that Trump transition officials may have been included in reports through ‘incidental collection’ during the surveillance of foreign intelligence targets.

Rather than share this information with the committee, however, he briefed the press, then rushed to the White House to tell the president about the matter. Although Nunes has promised to share the information he reviewed, as of Tuesday that has not occurred.

“This is sort of an Inspector Clouseau approach to this newfound evidence, whatever it is,” Republican Sen. Lindsey Graham told The Daily Beast. “I like Devin, I like him fine, but he should have not gone to the White House and gotten briefed himself. He should have had his committee members involved, in my view. And I think the only way you’re going to get this thing back on track is for him to disclose who he met with and what they saw and give it to the other people.”

Sen. John McCain, the chairman of the powerful Senate Armed Services Committee, said that Nunes must disclose his source. That’s something Nunes has said he won’t do.

“It’s absolutely necessary for him to describe exactly the sequence of events that led him to the actions and the narrative of his activities,” McCain said. “The American people deserve to know. This is very serious business. People’s names that were disclosed. I do not know what he’s talking about.”

By the end of the day Tuesday, Rep. Walter Jones, a contrarian Republican, became the first member of Nunes’ party to call for his recusal in the Russia investigation. And an article in the conservative National Review said that Nunes should step down as chairman of the intelligence committee.

Meanwhile, Nunes’s intelligence committee is in total disarray. Committee members told The Daily Beast that all their business has been indefinitely cancelled—whether it relates to the committee’s investigation into Russia or not.

“The committee has been frozen. We oversee an $80 billion operation. Our intelligence community is out there doing things that need oversight, let’s just put it that way,” said Rep. Jim Himes, a member of the House Intelligence Committee. “And we have been completely shut down. This week we’re not even doing our regular meetings.”

Rep. Eric Swalwell said he spoke to Nunes Tuesday and asked for a roundtable meeting with the members to clear the air. He said he didn’t think it would happen.

“Our investigation is stalled. And it’s unfortunate because the chairman—we want him to be credible on the other important duties that the committee has. Because we do a lot of stuff that is not Russia related. And he’s been successful in the past about having a functioning, bipartisan committee—whether it’s the cybersecurity bill, the reauthorization of the intelligence authorization act,” Swalwell said. “Everything now is stalled. We’re not even having our regularly scheduled meetings.”

“The chairman, I believe, if he recused himself, could get us back on track,” he added.