A federal judge has ruled that the Justice Department must turn certain portions of former special counsel Robert Mueller's grand jury evidence over to the House Judiciary Committee.

The documents must be turned over by Oct. 30. The order by the judge notes that the decision could be appealed, though it's not yet clear whether the decision will be appealed by the DOJ.

A Justice Department official told ABC News that the department is reviewing the decision.

The House Judiciary Committee first requested access to "certain" Mueller grand jury materials on July 26. The Department of Justice resisted this request, stating laws that prohibit the disclosure of information shared with grand juries.

But D.C. District Court Chief Judge Beryl Howell ruled in favor of the committee Friday, finding that, in light of the House's ongoing impeachment inquiry into President Donald Trump, the Department of Justice is "wrong" to assert all grand jury material need be kept secret.

"In carrying out the weighty constitutional duty of determining whether impeachment of the President is warranted, Congress need not redo the nearly two years of effort spent on the Special Counsel’s investigation, nor risk being misled by witnesses, who may have provided information to the grand jury and the Special Counsel that varies from what they tell HJC," Howell wrote.

According to Howell's findings, Volume I of the Mueller report includes 240 redactions on the basis of grand jury secrecy and Volume II includes "some but fewer" redactions on the same ground. Those redactions, and underlying material, must now be turned over to the committee.

In the court document, the judge wrote that several portions of the Mueller Report "are of particular interest" to the House Judiciary Committee, including "Trump Tower Meeting, Carter Page’s trip to Moscow, Paul Manafort’s sharing of internal polling data with a Russian business associate, and the Seychelles meeting, as well as information about what candidate Trump knew in advance about Wikileaks’ dissemination in July 2016 of stolen emails from democratic political organizations and the Clinton Campaign."

Access to the redacted material, the judge continued, is necessary for the committee to understand what the Special Counsel already found about those key events.

Also buried in Howell's ruling is an endorsement of the legality of Democrats' impeachment proceedings, which could undercut a major argument from the White House and Republicans on Capitol Hill and bolster Democrats' defense of their actions.

For weeks, Republicans have demanded Democrats hold a formal vote on the House floor to launch impeachment proceedings to legitimize the inquiry, clarify its scope and provide them with additional rights in the minority. The White House accused Democrats of launching an "illegitimate" impeachment effort, and vowed to stonewall Congress in the absence of a formal floor vote.

Howell dismissed the argument, accusing Republicans of cherry-picking historical precedent and writing that "no governing law requires this test" to officially launch impeachment.

"While close scrutiny of the historical record undercuts that justification for the “House resolution” test proposed by Representative [Doug] Collins, the more significant flaw with this proposal is as follows: while this test may address political legitimacy concerns, which are best resolved in the political arena, no governing law requires this test—not the Constitution, not House Rules, and not Rule 6(e), and so imposing this test would be an impermissible intrusion on the House’s constitutional authority both to “determine the rules of its proceedings," Howell wrote.

The judge also calls House Judiciary Committee ranking member Doug Collin's argument the House has not delegated the Judiciary Committee the power to start an impeachment inquiry, saying "These contentions are, at worst, red herrings and, at best, incorrect."

"The need for continued secrecy is minimal and thus easily outweighed by HJC’s compelling need for the material," the judge concluded. "Tipping the scale even further toward disclosure is the public’s interest in a diligent and thorough investigation into, and in a final determination about, potentially impeachable conduct by the President described in the Mueller Report."