Washington Commanders owner Daniel Snyder's attorney rejected the House Oversight committee's reasoning for wanting him to testify under a subpoena later this month, reiterating that he would do so voluntarily.

In a letter, attorney Karen Patton Seymour called the committee's concerns that her client would withhold information if not testifying under a subpoena "baseless."

On Tuesday, Committee Chairwoman Carolyn Maloney (D-N.Y.) accepted Snyder's offer to testify July 28 via videoconference, but said in a letter to Seymour that the committee would issue a subpoena and wanted a response from Snyder by noon today.

Though the subpoena was issued, it was not served to Snyder, who is still overseas, multiple sources said. U.S. marshals serve subpoenas on behalf of the committee in the United States but, according a spokesperson, the Marshals Service "has no authority to serve a Congressional subpoena internationally."

Seymour could accept the subpoena on Snyder's behalf but has not done so.

In October, Congress started investigating Snyder and Washington's workplace culture under his ownership, including claims of sexual misconduct. Approximately four months prior, the NFL concluded an investigation and fined Washington $10 million. Congress opened its investigation after complaints about a lack of transparency by the NFL into what was learned. Attorney Beth Wilkinson delivered her report orally, leading to the initial fine.

There's a difference between whether someone testifies voluntarily or under a subpoena, according to Dave Rapallo, Georgetown University's Federal Legislation Clinic director and the Democratic staff director of the House Committee on Oversight and Reform from 2011 to 2021.

"If you're under subpoena, you have to answer the question posed," Rapallo said. "If it's voluntary, and you're not under subpoena, you don't."

The committee's concern surrounded nondisclosure agreements as well. Maloney wrote that "you have made clear to Committee staff that a voluntary appearance would exclude matters covered by non-disclosure agreements." Maloney also asserted that Snyder has a "troubling history of using NDAs to cover up workplace misconduct."

Seymour responded by saying Snyder is not subject to any NDA that "conditions his ability to share information solely on receipt of a subpoena." She wrote that Snyder and the Commanders waived the NDAs to allow cooperation with Wilkinson as part of her investigation for the NFL.

Seymour also pointed out that the committee had invited him to testify voluntarily at a hearing June 22. NFL commissioner Roger Goodell testified at the hearing. But Snyder declined the invitation, saying he had a previous work engagement in France; he attended an awards ceremony.

"We are confident that Mr. Snyder will able to provide full and complete testimony during his voluntary appearance," Seymour wrote. "The July 12 letter also wrongly suggests that Mr. Snyder has previously refused to cooperate. To the contrary, since the Committee first requested that he appear voluntarily to testify at the June 22 hearing, Mr. Snyder has been fully committed to cooperating in the Committee's investigation."

Seymour proposed two dates that Snyder would be willing to testify: July 28 and July 29, the last two days the House is in session before going on recess for August.

The Commanders begin training camp on July 27. It hasn't been unusual for Snyder to miss the start of camp in recent years. He did not attend last year as his wife, Tanya, assumed responsibility for day-to-day operations of the team following the NFL's internal investigation of sexual misconduct and workplace culture allegations.

At the NFL meetings in March, Goodell said Snyder would not represent the team on a daily basis for the "foreseeable future" and that they would discuss his return "at some point." According to a league source, that discussion has not yet happened.

Seymour told the committee that Snyder was unavailable for most of July because he was in Israel observing the one-year anniversary of his mother's death with numerous events.

ESPN's Tisha Thompson contributed to this report.