Before he pleaded guilty and began assisting federal prosecutors last summer, Michael Cohen, President Donald Trump’s former fixer, spoke with a lawyer who agreed to reach out to the president’s legal team on his behalf.

The lawyer, Robert Costello, had about a dozen conversations with Trump’s lead lawyer, Rudy Giuliani, according to emails and documents reviewed by The New York Times and interviews with people involved in the matter. In one email, the discussions were characterized as a “back channel of communication.”

During one of the conversations last April, Costello said in an interview, he asked whether Trump might put a pardon “on the table” for Cohen, who was under federal investigation for a variety of possible crimes, including arranging hush-money payments to two women who had said they had affairs with Trump. Giuliani told Costello that the president was unwilling to discuss pardons at that time, Costello said in the interview, and they did not discuss it again.

Now federal prosecutors have requested the emails and documents from Costello, according to a copy of the request, which cited an investigation into “possible violations of federal criminal law” but offered no further detail. The request, sent last week, was for any documents related to Cohen as well as any bills Costello had sent him.

In one email, sent by Costello in April 2018 after a conversation with Giuliani, he assured Cohen, “Sleep well tonight, you have friends in high places.” He added, in a postscript: “Some very positive comments about you from the White House. Rudy noted how that followed my chat with him last night.”

A spokesman for the federal prosecutors, from the U.S. Attorney’s office in Manhattan, declined to comment.

There was no indication prosecutors suspected Costello of wrongdoing, and the focus of their inquiry is not clear.

Before calling Giuliani to ask about a pardon, Costello — a former federal prosecutor who had worked with Giuliani — warned Cohen that it was premature to broach the subject, but raised it anyway, he said Wednesday.

“He got a little annoyed,” Costello said, referring to Giuliani, his friend for decades. “I got the message. You only have to tell me once, Rudy.”

Giuliani insisted Wednesday that the discussions had primarily been about Cohen’s concerns that Trump “was very mad at him” and the fact that the investigation into Cohen had been assigned to the Manhattan prosecutors. Speaking by telephone, Giuliani said Costello and others in touch with Cohen had described him at the time as deeply distressed.

Last month, Cohen told the Senate Intelligence Committee in closed-door testimony about his dealings with Costello, which took place between April and July of last year, before he was charged with any crimes, according to two people familiar with his testimony.

He told the committee that Costello had raised the concept of a “pre-pardon” in his discussions with Cohen, the people said. In his public testimony before the House Oversight and Reform Committee, however, Cohen did not mention conversations about a pardon, and insisted he had never sought one from Trump.

By late last summer, after Giuliani had publicly discussed aspects of the case related to Cohen and the Trump organization had balked at paying some of his legal fees, Cohen had taken a new approach to his legal difficulties: turning on Trump and speaking with federal prosecutors and with Robert Mueller, the special counsel.

In August, he pleaded guilty to an array of crimes, including arranging the hush-money payments. And in testimony to Congress last month, he described Trump as a con man and a cheat, and said he was “ashamed that I chose to take part in concealing Mr. Trump’s illicit acts.” He is scheduled to begin serving a three-year prison term in May.

Less than a year ago, Cohen remained firmly entrenched in the Trump camp, and his extensive exchange with Costello suggested that he — and they — expected things would turn out differently.

In an email sent the day Giuliani was named as Trump’s lawyer, Costello told Cohen, “I am sure you saw the news that Rudy is joining the Trump legal team.” He added that he had told Cohen about his “relationship with Rudy, which could be very very useful for you.” Cohen wrote back, in part saying, “Great news.”

Within a day, Costello spoke by phone with Giuliani to tell him that Cohen was planning to hire Costello’s law firm. Soon after that call, Costello emailed Cohen to say, “Rudy was thrilled and said this could not be a better situation for the President or you,” noting that Giuliani knew and trusted Costello. Giuliani, he added, “said thank you for opening this back channel of communication.”

Later the same weekend, Costello sent the email about “friends in high places." Those two emails were first reported by CNN.

The Times reported last week that Cohen had described to the prosecutors how Costello had spoken with Giuliani. Costello declined to comment at the time, citing attorney-client privilege, but has since learned that Cohen waived the privilege, freeing him to discuss his experience with Cohen.

In the interview, Costello accused Cohen of smearing him to the prosecutors as part of a bid to reduce his sentence. He also said Cohen repeatedly told him that he had committed no crimes and misled Costello’s law firm about his intentions to hire them.

“Cohen lied to us from day one,” Costello said, adding that neither he nor Giuliani dangled a pardon in front of Cohen.

A lawyer for Cohen, Lanny J. Davis, said he could not comment on the documents requested by prosecutors, but suggested it was “impossible to deny or try to spin your way out of what documents say.” He added that Cohen had clarified his testimony about pardons in a letter to the House committee this week, and that Cohen stood by his statement to the committee about not having sought a pardon. Davis said after the testimony that Cohen had inquired about Trump’s intentions after the president’s legal team “dangled” the possibility of pardons.

In an email sent to Cohen on June 13, Costello suggested Giuliani was about to speak with the president, “his client,” and asked if he had a message to convey.

“Michael, Since you jumped off the phone rather abruptly, I did not get a chance to tell you that my friend has communicated to tell me that he is meeting with his client this evening and he added that if there was anything you wanted to convey, you should tell me and my friend will bring it up for discussion this evening. I would suggest that you give this invitation some real thought.”

This article originally appeared in The New York Times.