Agents also are providing protection to a man mistakenly identified on one Web site as being a witness in the case.
Federal officials won't tolerate anyone crossing the line from protected free speech to advocating violence in the wake of, said Richard K. Ruminski, the FBI's assistant special agent in charge of counterterrorism investigations in Chicago.
Ruminski said Tuesday that a couple of unnamed Web sites have been of particular concern, with views "almost threatening in nature."
One racist Web site posted an incorrect home address and cell and home phone numbers for FBI informant Anthony Evola, with the title "In Case Anyone Wants To Say Hi," Ruminski said. The address and phone numbers were really those of another man named Anthony Evola, not the person who was the key witness during Hale's trial, officials said.
"It concerns us to the point where we're going to see what legal actions can be taken in order to maybe legally take that Web site down," Ruminski said.
FBI agents and local police were providing round-the-clock protection to the other Anthony Evola, authorities said.
"You don't know who is going to show up at the house," said Joseph Evola, son of the wrongly identified Anthony Evola.
Hale, whose gospel of "racial holy war" was linked to a follower's shooting rampage five years ago that killed two people and the follower, was found guilty Monday of trying to have U.S. District Judge Joan Humphrey Lefkow killed.
Prosecutors said Hale was furious after Lefkow ordered him to stop using the name World Church of the Creator because it had been trademarked by an Oregon-based religious group that has no ties to Hale.
The Anthony Evola who testified at the trial said he became Hale's chief of security but was secretly working with the FBI because he was disgusted with Hale's racist fliers. He taped conversations with Hale in which they discussed the judge.
"Are we gonna exterminate the rat?" Evola can be heard asking Hale, who responds a short time later: "I'm going to fight within the law and, but, ... if you wish to, ah, do anything, yourself, you can."
The defense argued that Hale never asked anyone to kill the judge and that the FBI used Evola to draw him into a murder plot.