Billionaire Harlan Crow is lawyering up and refusing to disclose details to the Senate Finance Committee about luxury gifts provided to Justice Clarence Thomas.

In a letter to Chairman Ron Wyden of the Senate Finance Committee, Mr. Crow’s attorney, Michael Bopp, working on behalf of Gibson, Dunn, and Crutcher, said the committee’s request for records concerning Mr. Crow’s relationship with Justice Thomas lacked “legislative purpose.”

Mr. Bopp wrote that “we have serious concerns about the scope of and the authority for this inquiry,” adding that “the Committee’s powers to investigate are not unlimited.”

The letter in question was sent from the committee to Mr. Crow in order to “better understand any federal tax considerations arising from [Mr. Crow’s] gifts to Justice Thomas,” and to provide a “full accounting” to the American public.

Mr. Wyden went on to reiterate the claim maintained by Mr. Crow, that any gifts provided to Justice Thomas and his family were a matter of “personal hospitality” between people who “have been friends for well over two decades.”

Mr. Wyden also alleged that the committee’s letter is a component “of a broader campaign against Justice Thomas and, now, Mr. Crow, rather than an investigation that furthers a valid legislative purpose.”

The interest in the relationship between Mr. Crow and Justice Thomas has reached a boiling point following a ProPublica report from early April detailing their decades-long relationship.

The initial report found that Justice Thomas had received luxury travel on Mr. Crow’s private yacht and private jet without disclosing the trips as gifts.

The failure to disclose is potentially in violation of a law passed after Watergate that requires justices, judges, and members of Congress to disclose most gifts.

Since the initial report, other investigations have uncovered further aspects of Mr. Crow’s and Justice Thomas’s personal and financial relationship.

In mid-April, it was uncovered that Mr. Crow had bought property from Justice Thomas, which Mr. Crow maintains he plans to make it into a museum about the judge and his life. Justice Thomas failed to disclose the purchase.

Another ProPublica report from early May found that Mr. Crow was paying the $6,000 a month tuition to Hidden Lake Academy for a child who Justice Thomas had taken into his home to raise as his own.

These reports have generated an atmosphere of intense scrutiny concerning Justice Thomas and his relationship with Mr. Crow, eventually spurring the Senate Finance Committee into action.

With this escalation of the situation, Mr. Crow, as detailed in the letter from Mr. Bopp, has decided to lawyer up and resist attempts by the Senate to secure more information. It has also led to the discussion over a potential ethics code for the Supreme Court becoming more prevalent.