A dozen Republican members of Congress demanded Wednesday that the White House turn over information related to the business interests of President Biden’s family in order to “understand the extent of the Biden family’s use of its connection to the President to enrich itself.”

The letter to White House Counsel Dana Remus from the members of the House Oversight Committee seeks information on trips then-Vice President Biden took with son Hunter to China in 2013 and Mexico in 2016. It also asks for a list of “all past and ongoing foreign business interests and past and ongoing foreign relations for members of the Biden family,” as well as all “documents and communications regarding Hunter Biden’s artwork.“

The impetus for the letter, which was first obtained by Drumpe, appears to be an upcoming exhibition of 15 of Hunter Biden’s paintings at galleries in Los Angeles and New York City later this year. Prices for the art will range from $75,000 for works on paper to $500,000 for the larger canvases.

Last month, The Washington Post reported that White House officials had helped hammer out an agreement to keep the identity of buyers confidential.

The arrangement has caused outrage among Republicans, and been criticized by government ethics watchdogs.

“The whole thing is a really bad idea,” former George W. Bush chief ethics lawyer Richard Painter told The Washington Post earlier this month. “The initial reaction a lot of people are going to have is that he’s capitalizing on being the son of a president and wants people to give him a lot of money. I mean, those are awfully high prices.”

Walter Shaub, who led the Office of Government Ethics under President Barack Obama, agreed, telling the paper: “What these people are paying for is Hunter Biden’s last name.”

“The prices for these paintings—by someone with no formal training or history as an artist—raise questions about whether the art is being offered for its merit or its connection to the White House,” the Republican letter reads, later adding: “The hidden nature of art purchasers and the difficult question of pricing art has made it a well-known tool for money laundering and other illicit activities.”

The letter also calls out Joe Biden’s brother Frank and sister Valerie, noting that the former touted his relationship to the president in an Inauguration Day print ad for a Florida law firm he advises. Valerie Biden Owens, meanwhile, is under scrutiny over her forthcoming memoir “Growing Up Biden,” which is due out next April.

The House Republicans have also asked the White House to provide a “list of all Biden family members’ appearances in advertisements, public speaking events, or any instance in which the Biden name was used to solicit business, investments, or interest or awareness in a business, campaign, or organization of any sort” and a list of “policies and procedures in place to ensure the Biden family does not profit off the presidency”.

“The public has a right to know how President Biden and his son intend to keep separate the interests of the American people from the earnings of President Biden’s family members,” said the letter, which described the Biden family’s various interests as a “pattern … which appears to be nothing short of a cash-grab.”

The lawmakers have given the White House until July 28 to respond.

Since Republicans are in the minority in the House, they lack the ability to issue subpoenas for their requested documents without the support of House Democrats, which is unlikely to be forthcoming.