WASHINGTON – A second whistleblower "in connection to" the allegations surrounding the call between President Donald Trump and Ukrainian President Volodymyr Zelensky will be coming forward, according to that person's attorney.

"I can confirm that my firm and my team represent multiple whistleblowers in connection to the underlying August 12, 2019, disclosure to the Intelligence Community Inspector General," tweeted attorney Andrew Bajak, whose firm Compass Rose also represents the first whistleblower.

Mark Zaid, another Compass Rose lawyer, told ABC News about the firm's representation of a second whistleblower.

ABC News reported that the second whistleblower – "described as an intelligence official – has firsthand knowledge of some of the allegations outlined in the original complaint."

According to ABC, the second whistleblower had already contacted intelligence community inspector general Michael Atkinson but had not yet reached out to any of the House Intelligence Community or other congressional committees involved in the impeachment inquiry.

Rep. Jim Himes, D-Conn., said on CBS News' "Face the Nation" that the House Intelligence Committee has "not heard from a second" whistleblower, adding that "people around the president, professionals who are in the Oval Office, who are in the situation room, are watching what is happening and finally saying, 'My God, this cannot happen anymore.' "

The seven-page whistleblower complaint released to the public Sept. 26 had helped spark an impeachment inquiry by revealing that Trump had pressured Zelensky to open an investigation into his political rival former Vice President Joe Biden and his son Hunter Biden.

The complaint also said White House officials had tried to "lock down" details of the call.

Republicans had criticized the first whistleblower for not having firsthand knowledge of the call, though the intelligence community inspector general had found the complaint credible, and other information consistent with the complaint was publicly reported.

Trump has railed against the whistleblower as having the "facts wrong about the phone call" and tweeted on Saturday evening in response to a New York Times report Friday about a second whistleblower coming forward.

It is unclear if the whistleblower represented by Zaid is the same person.

"The first so-called second hand information “Whistleblower” got my phone conversation almost completely wrong, so now word is they are going to the bench and another 'Whistleblower' is coming in from the Deep State, also with second hand info. Meet with Shifty. Keep them coming," Trump wrote.

Zaid later tweeted what appeared to be a response to those who had criticized the first whistleblower for not having firsthand information.

According to Zaid, the second whistleblower had firsthand possession of "certain info," but "there is NO legal requirement for any (whistleblower) to have such knowledge. Law only requires a "'reasonable belief.'"

Rep. Chris Stewart, R-Utah, when asked on "Fox News Sunday" about a second whistleblower related to the Trump's call with Zelensky, said, "It does not matter."

"This person is going to come forward and say, 'Yep, the president had this phone call,' " Stewart said. "And yep, we have this transcript. Why should I care at all?"