Umar Farouk Abdulmutallab, the man accused of trying to blow up a jet airplane on Christmas Day, has been providing FBI interrogators with useful intelligence about his training and contacts since last week, Obama administration sources said Tuesday. Separately, FBI Director Robert S. Mueller III told senators at an intelligence committee hearing that Abdulmutallab was giving information to investigators. Mueller did not elaborate. The disclosures that the Nigerian student is cooperating with criminal investigators come amid a fierce debate in Congress over the Obama administration's handling of the case and, more broadly, its approach to national security. Dennis C. Blair,...