Cohen will speak for a second time privately with the House Intelligence Committee, which first met with him last week, after he took part in another closed-door session with the Senate Intelligence Committee and a public hearing with the House Committee on Oversight and Reform.
During the course of those interviews, both House and Senate investigators expressed a keen interest in the subject of pardons, which Cohen claims Trump's representatives dangled before him, according to people familiar with the matter. But others familiar with the matter said it was Cohen's lawyers who raised the pardon issue in such discussions.
The dispute is the latest in a politically-charged controversy surrounding Cohen's testimony and credibility as he shifts from being one of Trump's staunchest protectors to the most vocal accuser to emerge from the President's inner circle.
Cohen will soon start a three-year prison term for lies he told to Congress the last time he testified on Capitol Hill in 2017. Cohen has also testified that Trump's representatives made changes to what he planned to tell lawmakers then - a charge Trump's representatives have denied.
GOP lawmakers have argued that Cohen's past pattern of lying makes his current testimony suspect. In recent days, leading Republicans have also accused Intelligence Committee chairman Representative Adam Schiff, D, of coaching Cohen through his testimony.
Earlier this week, House Minority Leader Kevin McCarthy, R, suggested as much on Fox News, asking whether Schiff tried to "tamper" or "direct" Cohen to answer certain questions in a certain way and urging him to recuse himself from the investigation.
Today, intelligence panel member Representative Michael Turner, R, sent a letter to Cohen, asking him to disclose the number and nature of his contacts with Schiff, and saying that those contacts raised questions about "witness tampering, obstruction of justice, or collusion" - the same misconduct that Trump has been alleged to have engaged in.
Schiff called McCarthy's suggestions "frivolous" on Monday stressing that his contact with Cohen "was just inviting him to testify and also trying to allay his concerns about the President's threats against him and his family."
Cohen once cancelled a public hearing before the House Oversight Committee, citing threats he said Trump made against his family. The White House denied the allegation.
"Our staff certainly sat down to interview him," Schiff added, noting that "that's what you do in any credible investigation."
In response to Turner's letter, a spokesman for Schiff also characterised the committee staff's pre-interview contacts with Cohen as "proffer sessions," deeming them "completely appropriate."
"We are running a professional investigation in search of the facts," said Patrick Boland, intelligence committee spokesman. "Such sessions are a routine part of every serious investigation around the country, including congressional investigations."
A congressional aide also noted that Turner had not attended the intelligence panel's first closed-door session with Cohen.
As the parties argue over whether to believe Cohen's charges against Trump, his testimony is opening up several avenues of inquiry for the six House panels looking into allegations of wrongdoing in Trump's campaign and presidency. Those investigations are picking up steam as lawmakers brace for an expected report from Special Counsel Robert Mueller.
In the House Intelligence Committee, the recent hire of Daniel Goldman, a former federal prosecutor who prosecuted securities fraud, racketeering and organised crime, suggests that the panel will be taking a close look at Trump's finances and whether they were tied to foreign entities, Russian or otherwise, who could have leverage over the president. Schiff has also said he wants to look into questions of money laundering.
