(NewsNation) — The Senate Judiciary Committee is seeking more information after Chief Justice John Roberts declined a request to testify on the Supreme Court’s code of ethics.

In his letter declining to appear, Roberts attached a code of ethics, which he said all the justices voluntarily agree to follow.

Committee Chair Sen. Dick Durbin and committee Democrats submitted a list of questions to the justice, saying the ethics statement left more questions than it answered. A key question was if justices face any consequences for errors or omissions on financial reports. The committee is also seeking information on when justices agreed to adopt the code, whether the court requires a unanimous vote to adopt ethics resolutions, whether justices are made aware of which authorities they need to consult on ethics issues and if there is a process for the public to file complaints that a justice has failed to comply.

The committee requested the testimony after revelations that Justices Clarence Thomas and Neil Gorsuch has previously undisclosed financial ties that could impact their impartiality. ProPublica reported Thomas received luxury vacations from a wealthy Republican donor.

Thomas claims he was advised he did not have to disclose the information because the trips were personal gifts from someone he described as a close friend.

Reporting also showed Gorsuch had sold his home to a lawyer whose firm files briefs and argues before the Court. Although Gorsuch did disclose the sale of the home in financial disclosure, he did not name the buyer.

Two Senators have announced bipartisan legislation that would require the Court to adopt a code of conduct and appoint an official to oversee any possible violations from staff or justices.