Former advisor to U.S. President Donald Trump, Roger Stone, leaves the E. Barrett Prettyman United States Courthouse after being found guilty of obstructing a congressional investigation into Russia’s interference in the 2016 election on November 15, 2019 in Washington, DC.

No joke, Roger Stone engaged in "lowbrow character attacks," spun "conspiracy tales" and threatened to kill a friend's dog, but he does not deserve to go to prison — according to the comedian whose testimony led to the Republican operative's conviction on federal criminal charges.

Randy Credico, a New York radio personality, asked for mercy for Stone in an emotional letter this week to the judge set to sentence the longtime friend and political advisor of President Donald Trump for his crimes next month in U.S. District Court in Washington, D.C.

"I am writing to respectfully yet fervently implore you not to sentence Roger Stone to prison," wrote Credico, a former associate of Stone's, in his letter to Judge Amy Berman Jackson, which was placed on the court's docket Thursday.

"It is not justice" to send Stone to prison, Credico wrote. "It is cruelty."

The letter cites Stone's work with Credico in the early 2000s trying to reform New York state drug laws, and the emotional damage to Credico's own family from his father having served a decade in prison before getting married and having kids.

"I know the damage firsthand" from people going to prison, wrote Credico.