The Justice Department’s inspector general, Michael Horo­witz, is due to release his long-awaited findings in a week, but behind the scenes at the Justice Department, disagreement has surfaced about one of Horowitz’s central conclusions on the origins of the Russia investigation. The discord could be the prelude to a major fissure within federal law enforcement on the controversial question of investigating a presidential campaign.

Barr has not been swayed by Horowitz’s rationale for concluding that the FBI had sufficient basis to open an investigation on July 31, 2016, these people said.

It’s not yet clear how Barr plans to make his objection to Horowitz’s conclusion known. The inspector general report, currently in draft form, is being finalized after input from various witnesses and offices that were scrutinized by the inspector general. Barr or a senior Justice Department official could submit a formal letter as part of that process, which would then be included in the final report. It is standard practice for every inspector general report to include a written response from the department. Barr could forgo a written rebuttal on that specific point and just publicly state his concerns.

Spokespeople for the inspector general and the FBI declined to comment.

Justice Department spokeswoman Kerri Kupec said in a statement that the inspector general investigation “is a credit to the Department of Justice. His excellent work has uncovered significant information that the American people will soon be able to read for themselves. Rather than speculating, people should read the report for themselves next week, watch the Inspector General’s testimony before the Senate Judiciary Committee, and draw their own conclusions about these important matters.”

The Russia investigation was opened after the FBI was told of statements made by a then Trump campaign aide, George Papadopoulos, that the Russians possessed hacked Hillary Clinton emails. Papadopoulos’s alleged comments were key because they were made well before any public allegation that Russian intelligence operatives had hacked the Democratic National Committee.

The attorney general has privately contended that Horowitz does not have enough information to reach the conclusion the FBI had enough details in hand at the time to justify opening such a probe. He argues that other U.S. agencies, such as the CIA, may hold significant information that could alter Horo­witz’s conclusion on that point, according to the people familiar with the matter who spoke on the condition of anonymity to discuss internal deliberations.

Barr has also praised the inspector general’s overall work on the matter, according to one person familiar with the matter. The inspector general operates independently of Justice Department leadership, so Barr cannot order Horowitz to change his findings.

But the prospect of the nation’s top law enforcement official suggesting the FBI may have wrongly opened an investigation into a presidential campaign, even after the inspector general announces the agency was justified in doing so, will probably generate more partisan battles over how the Justice Department and the FBI operate.

It is not unusual for an attorney general or the Justice Department to disagree with some of an inspector general’s findings. However, typically those disagreements occur because senior leaders at the department believe the inspector general has been too critical. In this case, Barr has conveyed to others his belief that Horowitz has not been critical enough, or is at least reaching a conclusion prematurely.

People familiar with the draft language of Horowitz’s report said that while it is critical of some FBI employees, and found some systemic problems in surveillance procedures, it overall does not agree with Trump’s charge that the investigation was a “witch hunt” or a politically motivated attack on him first as a candidate and then as president.

Instead, the draft report found that the investigation was opened on a solid legal and factual footing, these people said.

Part of Barr’s reluctance to accept that finding is related to another investigation, one being conducted by the U.S. attorney in Connecticut, John Durham, into how intelligence agencies pursued allegations of Russian election tampering in 2016. Barr has traveled abroad to personally ask foreign officials to assist Durham in that work. Even as the inspector general’s review is ending, Durham’s investigation continues.

Barr’s disagreement with Horowitz will probably spark further criticism from Democrats, who have already accused Barr of using his position to protect the president and undermine federal law enforcement.

House Speaker Nancy Pelosi (D-Calif.) charged in September that Barr had “gone rogue.”

In recent weeks, Democrats have charged that Barr’s Justice Department was too quick to decide not to investigate Trump over his efforts to persuade Ukraine’s president, Volodymyr Zelensky, to announce an investigation of Democratic presidential candidate Joe Biden. The Ukraine controversy has led to an impeachment inquiry.

Criticism of Barr previously centered on his handling of the Russia investigation. The case that began in 2016 was taken over in May 2017 by special counsel Robert S. Mueller III. After a nearly two-year investigation, Mueller filed a lengthy report of his findings to Barr, by which point he had charged 34 people with crimes, including 26 Russian nationals. Those charged and convicted included Trump’s former campaign chairman, former personal attorney, former deputy campaign chairman and former national security adviser.

After receiving the Mueller report, Barr released a short letter summing up its main points, including that there was insufficient evidence to accuse any Trump associates of conspiring with the Russians. Barr also said Mueller had made no determination about whether Trump had sought to obstruct the investigation, but Barr and his then deputy concluded he had not.

When the full report was released, Democrats protested that Barr had improperly skewed the findings to be more favorable to Trump.

Barr has dismissed such criticism, and charged it is Democrats who are abusing legal procedures and standards in their quest to drive Trump out of the White House.

“In waging a scorched-earth, no-holds-barred war against this administration, it is the left that is engaged in shredding norms and undermining the rule of law,” Barr said in a speech last month.

In his first months on the job this year, Barr made clear he had serious concerns about how the FBI had conducted the investigation into possible collusion between Trump associates and Russia.

The attorney general declared in April that the Trump campaign was spied on, though aides later said he used that term not in a pejorative sense but in the more general meaning of surveillance.

“I think spying on a political campaign is a big deal,” Barr told lawmakers. “I think spying did occur, but the question is whether it was adequately predicated and I’m not suggesting it wasn’t adequately predicated, but I need to explore that.” He also criticized former leaders of the FBI, saying, “I think there was probably a failure among a group of leaders there in the upper echelon.”

Current and former law enforcement officials have said that, when presented with information about a possible plot to undermine the U.S. election, they had a duty to investigate, and that it would have been wrong not to have launched an investigation.

In the months since, Barr, through Durham, has pursued information related to a onetime associate of Papadopoulos, a European academic named Joseph Mifsud.

Mifsud was publicly linked to Russian interference efforts in late 2017, when Mueller revealed Papadopoulos had pleaded guilty to lying to the FBI about the details of his interactions with Mifsud.

Shortly after his name surfaced publicly, Mifsud told Italian media he did not work for Russia. “I never got any money from the Russians: my conscience is clear,” Mifsud told La Repubblica. “I am not a secret agent.”

Since then, the professor has disappeared from public life, leading to a host of theories about him and his whereabouts. While court papers filed in Mueller’s investigation suggested Mifsud operated in Russia’s interests, Papadopoulos, conservatives and conspiracy theorists have suggested he was working for Western intelligence agencies.