“His job was basically to publish information, which would cause other parties to act in a manner which would lead to their arrest,” Mr. Orozco said.

Prosecutors have acknowledged that Mr. Turner was an informant who spied on radical right-wing organizations, but the defense has said Mr. Turner was not working for the FBI when he reportedly made threats against Connecticut legislators and wrote that three federal judges in Illinois deserved to die.

“But if you compare anything that he did say when he was operating, there was no difference. No difference whatsoever,” Mr. Orozco said.

Special Agent Ross Rice, a spokesman for the FBI in Chicago, said he would not comment on or confirm Mr. Turner’s relationship with the FBI.