WASHINGTON, Nov 9 (Reuters) - U.S. intelligence officials are confident, but not certain, the English-speaking man who threatened new al Qaeda attacks in a videotape obtained by ABC News is a missing Californian named Adam Gadahn, ABC reported reported on Tuesday. After weeks of technical analysis, officials have concluded with a high degree of confidence that the speaker identified on the videotape as "Assam the America" is Gadahn, who left California for Pakistan six years ago, ABC reported. The CIA referred calls to the FBI. An FBI spokesman said he had no information on the reported identification. ABC obtained the...