WASHINGTON >> House Republicans say more investigation is needed into decisions made by the FBI and the Justice Department in 2016 as they brought an unceremonious end to their yearlong look at the department’s handling of probes into Democrat Hillary Clinton’s emails and Donald Trump’s ties to Russia.

In a letter released today, less than a week before Republicans cede the House majority to Democrats, the chairmen of two House committees described what they said was the “seemingly disparate treatment” the two probes received during the presidential election in 2016 and called on the Justice Department to appoint a special counsel to investigate further.

House Judiciary Chairman Robert Goodlatte and Rep. Trey Gowdy, House Oversight and Government Reform chairman, both of whom are retiring next week, sent a letter to the Justice Department and Senate Majority Leader Mitch McConnell saying they reviewed thousands of documents and conducted interviews that “revealed troubling facts which exacerbated our initial questions and concerns.” Republicans have said since the election that they believe Justice officials were biased against President Trump when they started an investigation into his ties to Russia and cleared Clinton in a separate probe into her email use.

The wrapping up of the congressional investigation, done in a letter and without a full final report, was a quiet end to a probe that was conducted mostly behind closed doors but also in public as Republican lawmakers often criticized interview subjects afterward and suggested they were conspiring against Trump.

The investigation’s most public day was a 10-hour open hearing in July in which former FBI special agent Peter Strzok defended anti-Trump texts he sent to a colleague as he helped lead both investigations. Strzok fought with Republican lawmakers in a riveting spectacle that featured Strzok reading aloud from his sometimes-lewd texts, and Democrats and Republicans openly yelling at each other.

Goodlatte and Gowdy laid out several concerns in the letter, many of them echoing a report issued this year by the Justice Department’s internal watchdog. That report concluded that Strzok’s anti-Trump text messages cast a cloud on the agency’s handling of the probe and also that fired FBI Director James Comey repeatedly broke from protocol, including when he announced his recommendation against charging Clinton. But unlike the congressional investigation, the report also found there was no evidence that Comey’s or the department’s final conclusions were motivated by political bias toward either candidate.

Democrats have blasted the GOP-led congressional probe, saying it was merely meant as a distraction from special counsel Robert Mueller’s Russia investigation. New York Rep. Jerry Nadler, the top Democrat on the judiciary committee, and Maryland Rep. Elijah Cummings, top Democrat on the oversight panel, are expected to end the investigation when they take power in January. Nadler has called it “nonsense.”

California Rep. Adam Schiff, who does not sit on either panel but is the top Democrat on the House intelligence committee, tweeted today that the Republican investigation is ending “not with a bang, but with a Friday, buried-in-the-holidays whimper, and one foot out the door.”

The Republicans have insisted that they were not trying to undermine the Mueller probe.

“Contrary to Democrat and media claims, there has been no effort to discredit the work of the special counsel,” Goodlatte and Gowdy wrote in the letter. “Quite the opposite, whatever product is produced by the special counsel must be trusted by Americans and that requires asking tough but fair questions about investigative techniques both employed and not employed.”

Republicans have repeatedly asked for a special counsel to look into the 2016 questions, but former Attorney General Jeff Sessions never granted their request. The department is now led by Acting Attorney General Matt Whitaker, who also received a copy of the letter.

Goodlatte and Gowdy have also asked for the Justice Department release transcripts from their investigation. The committees sent the transcripts to the department last week so they could be reviewed for any classified information, but they have not been released.