SACRAMENTO, Calif. - In a potential blow to their terrorism case against a father and son, federal prosecutors on Thursday said there is no evidence to support statements by their key witness that a top aide to Osama bin Laden attended a northern California mosque in the late 1990s. The surprise move was designed to dissuade the defense from calling witnesses who would challenge the story's credibility. The witness, an FBI informant, told agents when they recruited him in 2001 that he had seen a high-ranking al-Qaida official and two other international terrorists when he lived in Lodi during the...