Washington -- FBI agents Thursday conducted a second search of the Frederick, Md., home of Dr. Steven J. Hatfill, one of many current and former government scientists who have been interviewed about the anthrax mailings last fall.But a law enforcement official specifically rejected television reports that Hatfill was a "potential suspect." At least a dozen people are still under investigation, and warrants have been issued for other homes, offices and storage facilities throughout the country, the official said.