Jailed political extremist Lyndon LaRouche has filed a lawsuit to stop distribution of a newspaper column that he says could incite other inmates to harm him because it calls him a "cat-killer," a lawyer said.

The column by Mike Royko, syndicated through the Chicago Tribune, contends that LaRouche followers have killed cats of LaRouche opponents - a claim LaRouche followers deny."I hope that this column finds its way to his fellow inmates," Royko wrote in the column, printed Monday in the Chicago Tribune and distributed to about 500 newspapers. "They should know that they have a cat-killer in their midst. And I hope any cat-lovers among them do whatever they feel is appropriate."

Michael Null, the Chicago lawyer who filed the lawsuit in Cook County Circuit Court, said Thursday the column is "nothing less than inciting people to violence." Null said that is not something writers can do under constitutional protections of freedom of the press.