A handful of former federal prosecutors who signed a letter calling for the appointment of a special counsel last May now find themselves playing a role in the government's case against Michael Cohen, President Donald Trump's longtime personal attorney.

And it's not how you might think.

Last May, 180 former federal prosecutors who worked in the US attorney's office for the Southern District of New York signed on to a letter to Deputy Attorney General Rod Rosenstein calling for the appointment of a special counsel to oversee the FBI's investigation into Russian interference in the 2016 presidential election.

The letter came just days after President Donald Trump fired James Comey as FBI director.

Now, a handful of the signees find themselves involved in the case against Trump's longtime lawyer Michael Cohen.

Trump's attorney representing him in the case, Joanna Hendon, an accomplished trial attorney who used to work in the Manhattan US attorney's office, is a partner at Spears & Imes, a boutique law firm specializing in white collar criminal and civil litigation. Her partners, David Spears and Linda Imes, signed onto the letter. Hendon was not a signatory.

Additionally, two signatories to the letter were among the four nominees submitted by Cohen's attorneys to Judge Kimba Wood as options to serve as a special master, which Cohen's attorneys have sought to initially review the documents obtained by the FBI during the raids on Cohen's residences and office and make determinations on what is and is not covered by attorney-client privilege. Those two are Joan McPhee and Tai Park, former federal prosecutors who now work as defense attorneys.

The group of Republican, Democratic, and independent former federal prosecutors wrote that Comey's "abrupt and belated termination for" conduct related to the investigation into 2016 Democratic presidential nominee Hillary Clinton's use of a private email server that occurred after "his public testimony about his oversight of the investigation of Russian interference with the 2016 presidential election, has the appearance – if not the reality – of interfering with that investigation."

"Even if this investigation continues unabated, there is a substantial risk that the American people will not have confidence in its results, no matter who is appointed to succeed him, given that the Director of the FBI serves at the pleasure of the President," the letter continued. "We believe it is critical in the present political climate and clearly in the public’s interest that this investigation be directed by a truly independent, non-partisan prosecutor who is independent of the Department of Justice."

Park and a representative for McPhee declined to comment. Spears and Imes did not immediately respond to a request for comment from Business Insider.

Read the full May 2017 letter:

"We, the undersigned, are former United States Attorneys and Assistant United States Attorneys for the Southern District of New York. In view of the recent termination of James Comey as Director of the Federal Bureau of Investigation, we are writing to request that you appoint a special counsel to oversee the FBI’s continuing investigation of Russian interference with the 2016 Presidential election and related matters. This letter is addressed to you rather than the Attorney General since he has recused himself from this matter."

"As you know, Jim has had a long and distinguished career with the Department of Justice, beginning with his appointment as an Assistant United States Attorney in the Southern District of New York serving under United States Attorneys Rudolph Giuliani, Benito Romano and Otto Obermaier from 1987 through 1993. He returned to the Southern District of New York in 2002 when he was appointed the United States Attorney and served in that capacity until he was confirmed as Deputy Attorney General in 2003. Most of us came to know Jim when he worked in the Southern District of New York. Many of us know him personally. All of us respect him as a highly professional and ethical person who has devoted more than 20 years of his life to public service."

"While we do not all necessarily agree with the manner in which he dealt with the conclusion of the Hillary Clinton email investigation, we sincerely believe that his abrupt and belated termination for this conduct, occurring months later and on the heels of his public testimony about his oversight of the investigation of Russian interference with the 2016 presidential election, has the appearance – if not the reality – of interfering with that investigation. Even if this investigation continues unabated, there is a substantial risk that the American people will not have confidence in its results, no matter who is appointed to succeed him, given that the Director of the FBI serves at the pleasure of the President. We believe it is critical in the present political climate and clearly in the public’s interest that this investigation be directed by a truly independent, non-partisan prosecutor who is independent of the Department of Justice, as is contemplated by 28 C.F.R. §600.1."

"We are Republicans, Democrats and independents. Most importantly, we are proud alumni and alumnae of the Department of Justice. We do not suggest that you or any other members of the Department of Justice or a newly appointed Director of the FBI would not conduct yourselves properly, but the gravity of this investigation requires that even the appearance of political involvement in this investigation be avoided. As former prosecutors, we believe the only solution in the present circumstances would be to appoint a Special Counsel pursuant to 28 C.F.R. §600.1, and we urge you to take that course."