Republicans on the House judiciary committee on Friday announced an investigation into the discovery of classified documents at Joe Biden’s Delaware home and former office in Washington DC.

The GOP representatives, newly in control of committees after their party took the House last November, made their move a day after the attorney general, Merrick Garland, announced the appointment of a special counsel to investigate the matter.

In a letter to Garland, the judiciary committee chair, Jim Jordan of Ohio, said: “We are conducting oversight of the justice department’s actions with respect to former vice-president Biden’s mishandling of classified documents, including the apparently unauthorized possession of classified material at a Washington DC private office and in the garage of his residence in Wilmington.

“On 12 January 2023, you appointed Robert Hur as special counsel to investigate these matters. The circumstances of this appointment raise fundamental oversight questions that the committee routinely examines. We expect your complete cooperation with our inquiry.”

The letter noted that the documents were discovered just before the midterm elections, and accused the justice department of departing “from how it acted in similar circumstances”, namely the inquiry into government secrets found at Donald Trump’s Mar-a-Lago resort.

A special counsel, Jack Smith, has been investigating Trump since November – an announcement made after the midterm elections.

The Republican congressmen demanded Garland turn over an array of documents related to the Biden investigation by 27 January.

The judiciary committee investigation was the second announced by House Republicans since the documents’ discovery was reported this week.

The first is being pursued by the new oversight committee chair, James Comer, a Kentuckian who is playing a major role in the Republicans’ campaign of investigations against the Biden White House.

Earlier on Friday, Comer sent the White House a demand for information about whether Hunter Biden, the president’s son who is a magnet for Republican investigations and accusations, had access to the garage at the Delaware residence.

An oversight committee tweet said: “We have doc[ument]s revealing this address appeared on Hunter’s driver’s license as recently as 2018, the same time he was cutting deals with foreign adversaries. Time for answers.”

Even before Biden took office, Republicans tried to find evidence of corruption in Hunter Biden’s business dealings, and of his father’s involvement. Hunter Biden’s dealings in Ukraine were at issue in Trump’s attempts to procure dirt on Joe Biden, a scheme which led to the first of Trump’s two impeachments.

Such efforts to ensnare Joe Biden via his son have achieved mixed results at best but this week’s revelations about classified documents in the elder Biden’s possession have produced new lines of attack.

Speaking to CBS, Jordan said: “Right now there are tons of questions. A lot of those I think will be answered in the intelligence committee and the oversight committee. But we’ll be looking at the justice department component.”

A third committee joined the hunt on Friday, with a letter to defense officials from Mike Rogers, the chair of the House armed services committee.

The proliferating investigations have provided a new headache for Democrats in Congress.

The party has been on a roll, doing much better in the November midterms than expected, before the gifts of Republican disarray in the House and a surprisingly quiet presidential campaign from Trump.

Asked on CNN on Friday if he believed Biden broke the law by retaining classified documents, the Senate majority leader, Chuck Schumer, said: “It’s much too early to tell.

“I think President Biden has handled this correctly. He’s fully cooperated with the prosecutors … it’s a total contrast to President Trump, who stonewalled for a whole year.”

Schumer called for patience.

“We should let it play out, we don’t have to push [the special counsels] in any direction or try to influence them,” he said. “Let [them] do their job.”

Schumer said he supported the appointment of Robert Hur in the Biden case.