More than 100 former judges, attorneys general and prominent politicians have signed a letter supporting Sholom Rubashkin, the Iowa kosher slaughterhouse executive sentenced to 27 years in prison for fraud and money laundering.

The letter supports the claim by Rubashkin’s attorneys that prosecutors used improper tactics in securing the lengthy sentence for Rubashkin, according to the Des Moines Register.

Among the signers are John Ashcroft, Michael Mukasey, Edwin Meese III and Ramsey Clark, who served as attorneys general under Presidents George W. Bush, Ronald Reagan and Lyndon Johnson, respectively. Others include the former Sen. Joe Lieberman of Connecticut and ex-New York City Mayor Rudy Giuliani.

The letter was written on April 19 to Kevin Techau, the U.S. attorney for the Northern District of Iowa, who is overseeing the case.

Rubashkin’s lawyers say federal prosecutors interfered illegally with the bankruptcy sale of Agriprocessors, Rubashkin’s kosher meat plant in Postville, Iowa, by ensuring that no members of the Rubashkin family were among the plant’s buyers. The company sold for $8.5 million despite its $35 million line of credit.

According to the attorneys, the interference led to the company’s losses being figured at a higher number, exacerbating Rubashkin’s offenses and thus resulting in a longer prison term.

“This conduct resulted in Mr. Rubashkin receiving an effective life-sentence for nonviolent offenses against a financial institution, despite considerable mitigating personal circumstances, including being a 51-year-old, first-time offender and father of 10,” read the letter to Techau, according to the Register. “We respectfully submit that it is your duty to ensure that the miscarriage of justice that Mr. Rubashkin’s extreme prison sentence represents is now remedied, not perpetuated.”

In 2012, more than 80 former federal judges supported an unsuccessful request to the U.S. Supreme Court to hear an appeal of the Rubashkin case.