A man accused of being a white supremacist has pleaded not guilty to planning to bomb a historic Colorado synagogue. Federal public defender Mary Butterton entered three not guilty pleas Monday on behalf of 27-year-old Richard Holzer in U.S. District Court in Denver. Holzer watched the brief hearing in shackles and a yellow jail jumpsuit. Members of Temple Emanuel sat together in the back of the courtroom. Holzer is charged with attempting to obstruct the exercise of religion by force by using explosives and fire against Temple Emanuel in Pueblo. He also is charged with attempted arson and using fire or an explosive device to commit a felony. Holzer was arrested Nov. 1 after the FBI said he accepted what turned out to be phony explosives from undercover agents.