The House Select Committee investigating the Jan. 6 insurrection at the U.S. Capitol has issued subpoenas to four individuals with close ties to former President Donald Trump .

On Thursday, the panel demanded documents and testimony from former White House chief of staff Mark Meadows, former Trump social media chief Dan Scavino , former Defense Department official and House Intelligence Committee aide Kash Patel and former Trump adviser Steve Bannon. These four witnesses were working in the Trump White House or had communications with it on or in the days leading up to Jan. 6.

The Committee is investigating the facts, circumstances, and causes of the January 6th attack and issues relating to the peaceful transfer of power, to identify and evaluate lessons learned and to recommend corrective laws, policies, procedures, rules, or regulations, Chairman Bennie Thompson (D-Miss.) wrote in a statement.

The subpoenas instruct Patel and Bannon to appear at an Oct. 14 deposition, and Meadows and Scavino to appear the next day. All four must produce relevant documents by Oct. 7.

The letters Thompson sent to each witness cite both news reports and documents obtained by the committee that suggest these Trump associates have information relevant to the Jan. 6 probe.

In his letter to Meadows, the chairman wrote that the panel has revealed credible evidence of your involvement in events within the scope of the investigation and that the former chief of staff has critical information regarding many elements of our inquiry.

As chief of staff, Meadows allegedly communicated with officials at the state level and in the Justice Department as part of an effort to overturn the results of the 2020 election or prevent its certification, according to the committee. Meadows also communicated with organizers of the Jan. 6 rally, including Amy Kremer of Women for America First, ProPublica previously reported .

The panel said it had previously sought out White House records relating to Meadows, including his actions, communications and information he received dealing with the elections results and integrity.