WASHINGTON (Reuters) - A computer used by Paula Broadwell, the woman whose affair with CIA Director David Petraeus led to his resignation, contained substantial classified information that should have been stored under more secure conditions, law enforcement and national security officials said on Wednesday. The contents and amount of the classified material - and questions about how Broadwell got it - are significant enough to warrant a continuing investigation, the officials said. They spoke on condition of anonymity because they are not authorized to comment publicly. The details about material held by Broadwell, a reserve officer in military intelligence, emerged...