WASHINGTON (Reuters) – Amazon.com Inc (AMZN.O) Chief Executive Jeff Bezos is willing to testify to a congressional panel investigating potential violations of U.S. antitrust law by big technology companies, according to a letter from an attorney representing Amazon.

The letter to members of the House Judiciary Committee said Amazon had cooperated with the panel’s probe. “This includes making Jeff Bezos available to testify at a hearing with the other CEOs this summer,” said the letter, signed by Robert Kelner of Covington and Burling LLP.

A copy of the letter was seen by Reuters.

The big four tech platforms — Alphabet Inc’s (GOOGL.O) Google, Apple Inc (AAPL.O), Amazon and Facebook Inc (FB.O) — are under investigation by a House Judiciary Committee panel and the U.S. Justice Department. Meanwhile, the Federal Trade Commission is probing Facebook and Amazon and groups of U.S. state attorneys general are looking at Facebook and Google.

Kelner said in the letter that Amazon and the committee would need to “resolve a number of questions regarding timing, format, and outstanding document production issues, all necessarily framed by the extraordinary demands of the global pandemic.”

Further, the letter also noted that Amazon had given the committee’s antitrust panel large numbers of documents totaling more than 225,000 pages and notes that the committee has not given a “binding commitment” that the documents would be treated as confidential.

The committee did not immediately respond to a request for comment.