Michael Cohen, the key witness in President Trump’s ongoing hush-money trial, whose testimony has not yet finished, is already being accused of lying by the lawyer with whom he consulted extensively in 2018 as his legal predicament deepened.

“I read Michael Cohen’s testimony from yesterday’s trial in New York on the way down on the train, and virtually every statement he made about me is another lie,” the attorney, Robert Costello said on Wednesday in an appearance on Capitol Hill before the House Select Subcommittee on the Weaponization of the Federal Government. 

Mr. Costello gave Cohen legal advice in 2018, as Cohen was becoming entangled in Special Counsel Robert Mueller’s Russia investigation targeting Mr. Trump. After the Wall Street Journal reported on a possibly illegal $130,000 hush money payment Cohen paid to the porn star Stormy Daniels, FBI agents, acting on a criminal referral from Mr. Mueller, raided Cohen’s home and offices in April 2018.

Cohen described the raid during his testimony. He was staying at a hotel, because his apartment was flooded, when the FBI knocked at his door early in the morning. 

“At 7 o’clock in the morning, there is a knock on the door and I look through the peephole and I see a ton of people out in the hallway. I saw a badge … they identified themselves at the FBI,” Cohen said. He further testified that he felt frightened, and “Concerned. Despondent. Angry.”

According to his testimony, Cohen left a message for Mr. Trump right away. And the then-president called him back, Cohen said. 

“I received a phone call from President Trump in response to me leaving a message for him to call,” Cohen testified. “I wanted obviously for him to know what was taking place. He said, don’t worry, I am the president of the United States. There is nothing here. Everything is going to be OK. Stay tough. You are going to be OK.” This was the last time he spoke to Mr. Trump, Cohen said. 

But Mr. Costello would serve as a conduit between Cohen and the White House, where Mr. Trump’s lawyers were grappling with Mr. Mueller’s investigators. The relationship between Mr. Costello and Cohen eventually soured, partly over unpaid legal bills, as Cohen’s legal woes deepened. In subsequent years, Mr. Costello, who has also represented Rudolph Giuliani, has sought to undermine Cohen’s credibility..

“Now, after going to jail, Michael Cohen is on a revenge tour because he blames Donald Trump for the loss of his law license and the fact that he did go to jail,” Mr. Costello said at the hearing, adding that Cohen said about him that he “conspired to obstruct justice by dangling a pardon for him to keep his mouth shut about Donald Trump.” Mr. Costello added, “That was totally false and utter nonsense.”   

Cohen, who worked for Mr. Trump from 2006 until 2018, was disbarred  after he pleaded guilty to lying to Congress, campaign finance violations, tax evasion and other charges, all related to his work for Mr. Trump who was the target of prosecutors. Cohen was sentenced to three years in federal prison and three years of supervised release, serving 13 1/2 months behind bars and a year and a half in home confinement on Manhattan’s Upper East Side. Today, Cohen is still on probation. He has asked the court three times for an early release, but was denied every time. 

In 2018, Cohen was charged, among other things, with making a $130,000 hush-money payment to Stormy Daniels, whose real name is Stephanie Clifford. This issue is at the heart of the case the Manhattan district attorney, Alvin Bragg, has brought against Mr. Trump, currently being tried at the Manhattan criminal court.

Ms. Clifford claims she had a one time sexual encounter with Mr. Trump during a celebrity golf tournament at Lake Tahoe in 2006. Mr. Trump denies this allegation. The prosecution accuses Mr. Trump of directing Cohen to pay Ms. Clifford the $130,000 on the eve of the 2016 election, so she would sign a non-disclosure agreement that prohibited her from sharing her story. The prosecution further alleges that Mr. Trump reimbursed Cohen after he won the presidency by fraudulently disguising the payments as legal fees.

On Monday and Tuesday, Cohen testified for the prosecution and described in detail how this hush-money payment was part of a larger scheme, devised by Mr. Trump, David Pecker, the former publisher of the National Enquirer, and Cohen, to manipulate the public opinion by eliminating bad press about Mr. Trump. Cohen told jurors that Mr. Trump personally directed him to pay Ms. Clifford. 

But on Wednesday, Mr. Costello told Congress that Mr. Trump was not actually involved in the payment to Ms. Clifford. Instead, he said, Cohen acted on his own, wanting to protect Mr. Trump’s wife, Melania, and his own wife.    

“He focused on Melania Trump. He said, ‘I didn’t want to embarrass Melania Trump.’ He said, ‘that’s why I decided to take care of this on my own,’’’ Mr. Costello testified on Capitol Hill, adding that Cohen said he didn’t want anyone to know where he got the money. “I didn’t want Melania to know. I didn’t want my wife to know,” Cohen said, according to Mr. Costello’s testimony. 

Mr. Costello also told Congress that Cohen swore to him that he didn’t have “anything on Donald Trump,” and that “Cohen must have said this at least ten times because I kept coming back to it from different approaches.” 

But on the witness stand at Manhattan, Cohen portrayed Mr. Costello as being “really sketchy and wrong,” when the prosecution asked him about their relationship. After the FBI raid, Cohen told the jury, Mr. Costello emailed him that he didn’t need to worry. The email, which was shown in court, read, “Sleep well tonight, you have friends in high places.” Cohen explained this to be a direct reference to the then-president Mr. Trump, who had the power to pardon him.

Mr. Costello, Cohen said on the witness stand, offered to represent him in 2018, saying this would be “very beneficial for you going forward with this matter.” The jury was shown another April 2018 email from Mr. Costello to Cohen, informing Cohen that Mr.  Guiliani had also joined the Trump legal team – which was handling the same federal probe that had ensnared Cohen – and would also help to get Cohen out of his legal mess. 

“I am sure you saw the news that Rudy is joining the Trump legal team,” the email read. “I told you my relationship with Rudy which could be very useful to you.” 

Cohen laid out what he called, “the concept of the back channel.” Mr. Costello would communicate with Mr. Guiliani who then would communicate with Mr. Trump. He testified that Mr. Costello was pressuring him to “stay in the fold,” meaning to stay loyal and not turn on Mr. Trump. 

By summer of 2018, Cohen testified, Mr. Trump was carrying out a “pressure campaign” on him through Mr. Costello.

“You are making a very big mistake if you believe the stories these ‘journalists’ are writing about you. They want you to cave. They want you to fail. They do not want you to preserve and succeed,” Mr. Costello wrote in an email to Cohen, which prosecutors presented to the jury. “If you really believe you are not being supported properly by your former boss, then you should make your position known.”

Cohen told the court that this meant, “Don’t flip. Don’t speak. Don’t cooperate.”

When Cohen decided not to retain Mr. Costello and speak to other attorneys, Mr. Costello got upset, Cohen testified, saying Mr. Costello was “again pressuring me as he had done with constant calls and sending me emails and so on. He wanted to absolutely be retained to represent me in this matter. He was angered that I was willing to sit down with another attorney but not sit down with them, so I had enough.”

On Wednesday, Mr. Costello fiercely disagreed, saying, “When they claim that I was trying to shut up Michael Cohen, it’s exactly the opposite. I was on that first day telling him, here’s your escape route. If you have truthful information, but he didn’t.” 

The question is, how can the defense use Mr. Costello’s testimony at trial on Thursday? They can ask Cohen if he is familiar with Wednesday’s Congressional hearing. But he can simply say, he is not. Any further reference to Mr. Costello’s statements would be considered hearsay in court, unless the defense has text messages or emails to substantiate Mr. Costello’s claims. But if such emails do in fact exist, the prosecution has also seen them. The defense could call Mr. Costello as a witness, but then the district attorney could also cross-examine him. 

Regardless, Cohen’s testimony on Thursday will likely spark a fierce battle between the attorneys. After Mr. Trump’s defense attorney finishes his questioning, Cohen will most probably face another round of questions from the prosecution, which can then be followed by another re-cross-examination from the defense, and another round by prosecutors. This intense back and forth could last for hours – it did when Mr. Pecker, the former publisher of the National Enquirer, testified two weeks ago. 

At stake is Cohen’s credibility and the essential question of whether Mr. Trump was personally involved in the hush-money payment or not.