Senate Judiciary Committee Chairman Lindsey Graham (R-S.C.) ripped the FBI's investigation into Trump campaign associates on Monday, arguing it was a "criminal enterprise" and showed a system that "got off the rails."

"I believe there will be no debate among reasonable minded people ... about how the system not only got off the rails but, in my view, became a criminal enterprise to defraud the FISA [Foreign Intelligence Surveillance Act] court, to deny American citizen Carter Page his constitutional rights and to continue an operation against President Trump as president of the United States that I think was fundamentally flawed and unlawful," Graham said during a press conference.

His remarks to reporters followed the release of Justice Department inspector general Michael Horowitz's findings from a two-year investigation into the FBI's decision to open up a probe during the 2016 campaign into Trump associates.

Graham brushed off divisions between Horowitz and Attorney General William Barr about whether there was enough information to initiate the 2016 probe, saying that "lawyers can reasonably disagree."

"Let's assume for a moment it started out OK; it sure as hell didn't end OK," Graham added.

The South Carolina Republican, who has emerged as one of Trump's most vocal defenders on Capitol Hill, accused the FBI of going back "to the good old days of J. Edgar Hoover" and that FBI officials "made stuff up."

"If I was Mr. Carter Page, I'd hire me a lawyer and I'd sue the hell out of the United States," Graham said.

Horowitz, in his report, concluded that the FBI's decision to open an investigation was not motivated by political bias. He also concluded that the FBI had "an authorized purpose" to launch a probe to "obtain information about, or to protect against, a national security threat or federal crime, even though the investigation also had the potential to impact constitutionally protected activity."

The inspector general outlined seven "significant inaccuracies and omissions" in the FBI's application to the Foreign Intelligence Surveillance Court to monitor Page, some of them related to the information received from Christopher Steele, an ex-British intelligence agent who authored the Trump-Russia dossier.

"We found that members of the Crossfire Hurricane team failed to meet the basic obligation to ensure that the Carter Page FISA applications were 'scrupulously accurate,' " the report states.

Graham pointed to Horowitz's finding that interviews with a "primary sub-source" of the dossier "raised significant questions about the reliability of the Steele election reporting."

"What they did from that point on, this whole endeavor became a criminal conspiracy to defraud the court, to trample on the rights of an American citizen, Mr. Carter Page," Graham said.

He added that "if that doesn't bother you, you hate Trump way too much."

Horowitz is scheduled to testify about his findings before Graham's committee this week.

"On Wednesday, we're going to have a hearing, and we're going to get the good, the bad and the ugly," Graham said.

GOP senators on the panel signaled Monday that they have significant concerns about Horowitz's findings.

"Anyone who values fundamental civil liberties in the United States should be disgusted and terrified by what the inspector general uncovered in today's report on the FBI's spying on an American citizen. That such abuse was carried out against a citizen working on a political campaign is just that much more disturbing," Sen. Chuck Grassley (R-Iowa) said in a statement.

Sen. Thom Tillis (R-N.C.), another member of the panel, said the initial results are "deeply disturbing, revealing numerous missteps and interference during the FBI's investigation."