The Jan. 6 committee investigating the attack on the U.S. Capitol has yet to formally subpoena former President Donald Trump, in part because investigators are still trying to find someone authorized to accept service of it, sources familiar with the matter tell ABC News.
Last week, the committee took the historic step of voting to subpoena the former president, with all nine members of the panel voting to approve the resolution to compel him to testify about the attack on the Capitol, which the committee argues was the violent culmination of Trump's many efforts to overturn the 2020 election.
But multiple lawyers representing Trump have told committee investigators they aren't permitted to formally accept service of the subpoena on behalf of Trump, sources familiar with the deliberations say.
MORE: With Trump subpoena likely this week, what's next for the Jan. 6 committee?The subpoena is expected to be issued in short order once committee investigators learn who is formally representing Trump in the matter, and after the panel agrees to additional details regarding deadlines for Trump's compliance and the precise details of the documents they are seeking. The subpoena could be issued as soon as Thursday, the sources said.
Rep. Liz Cheney said on Tuesday the formal request from the committee would happen "shortly."
Trump has increasingly had trouble finding representation for the various legal challenges he's facing, sources have told ABC News.
Both Evan Corcoran and John Rowley have told committee investigators they don't have authorization to accept service of the subpoena on behalf of the former president, according to people familiar with the communications. Corcoran is representing Trump in matters related to the Mar-a-Lago documents probe and Rowley -- in addition to Corcoran -- has been representing Trump on executive privilege issues involving former White House aides who have received grand jury subpoenas.
The committee has also contacted attorney Justin Clark, who has said he also isn't authorized to accept it, sources say.
Neither Corcoran, Rowley or Clark responded to ABC News' request seeking comment.
A spokesperson for Trump did not respond to a request for comment, and a spokesperson for the Jan. 6. committee declined to comment.
Trump has previously told advisers that he'd welcome a live appearance before the committee, according to sources familiar with his thinking, but he has yet to say publicly whether he'll cooperate. He has denounced the committee and the Jan. 6 investigation.
And if Trump were to offer to testify live in response to the panel's subpoena, the committee would need to negotiate the terms of such an appearance.
MORE: In historic move, House Jan. 6 committee votes to subpoena Trump"I think that's going to be a negotiation," committee member Adam Kinzinger, R-Ill., told ABC News' "This Week."
"I'll only address that when we know for sure whether or not the president has tried to push to come in and talk to us live," Kinzinger said.
In a 14-page memo addressed to committee Chairman Bennie Thompson and posted to social media on Friday, Trump did not answer whether he would comply with the subpoena to testify. He instead continued his attacks on the panel and continued to make false claims about the 2020 election.
"This memo is being written to express our anger, disappointment, and complaint ... with all of the hundreds of millions of dollars spent on what many consider to be a Charade and Witch Hunt," he wrote.