Investigators believe the Air India Boeing Dreamliner had its emergency-power generator operating when it crashed last week in India's Ahmedabad, the Wall Street Journal reported on Wednesday citing people familiar with the probe.

Last year, the F.A.A. said it was also investigating claims by a Boeing engineer that parts of the fuselage, or body, of the Dreamliner were improperly fastened together, which the whistle-blower said could cause premature damage to the plane over years of use.